It has been established in animals that somatostatin (SST) is released from pain-activated sensor... more It has been established in animals that somatostatin (SST) is released from pain-activated sensory nerve endings and exerts systemic antinociceptive and anti-inflammatory actions. The aim of this study was to investigate the changes of SST-like immunoreactivity (SST-LI) in human serum before, immediately after and 2 h after surgical operations. 25 patients were enrolled in the study. Laparoscopic cholecystectomy, abdominal wall hernia or inguinal hernia operations were performed under combined anesthesia. A 5-ml blood sample was drawn from each patient, the blood was centrifuged and the serum frozen. SST-LI was determined from the defrosted samples by radioimmunoassay. Abdominal surgical operationsinduced a significant increase of SST-LI in the serum. 2 h later it was restored in the cases of laparoscopic interventions but still remained elevated after hernia surgeries. In this human study we showed for the first time that surgical interventions elevate the endogenous SST-LI in human serum. It is assumed that the released SST is derived from the activated sensory nerves. Since antinociceptive and anti-inflammatory effects of neural SST have already been established in laboratory animals, we presume that this endogenous protective mechanism also operates in humans.
Hydrogen sulfide (H2S) is a toxic gas. It has been recognized that H2S evolving in biochemical re... more Hydrogen sulfide (H2S) is a toxic gas. It has been recognized that H2S evolving in biochemical reactions in living organisms has an important role in different physiologic processes. Nowadays, H2S is known as an endogenous messenger molecule. Natural sulfurous spring water has been proved beneficial in the therapy of diseases of the skin and other organs (Boros et al 2013). In vivo real-time detection of local H2S concentration is an important but challenging task.We developed a two-electrode amperometric cell for selective subcutaneous detection of H2S in anesthetized mice. The cell is a small size implantable gas sensor containing a platinum disc anode and a silver cathode. The selectivity is provided by a membrane permeable only by gases. There is a buffered reversible electrochemical mediator solution in an oxidized form inside the cell. As gaseous H2S penetrates into the cell the mediator is reduced, and +0.4 V versus the reference is employed on the platinum working electrode. The reduced mediator is oxidized on the anode surface. The current provides an analytical signal representing the concentration of H2S.Appropriate shape, size and membrane material were selected, and optimal working parameters--such as mediator concentration, pH and cell voltage--were determined in vitro. The lower limit of detection in the stirred sample solution at pH = 5.5 was as small as 9.4 × 10(-7) M and a dynamic concentration range of 0-6 × 10(-4) M could be achieved.The detecting surfaces of the cell were covered with freshly dissected mouse skin to test dermal H2S permeability. In other experiments, the cell was implanted subcutaneously in an anesthetized mouse and the animal was submerged in a buffer solution containing different concentrations of H2S so that the skin surface over the sensor was covered by the solution. Measurements of subcutaneous H2S concentration were taken. The experiments clearly proved that H2S diffuses through the skin of the live mouse.
The present study investigates the effect of oral consumption of hydrogen sulfide-containing Hark... more The present study investigates the effect of oral consumption of hydrogen sulfide-containing Harkány thermal spring water, as well as sodium hydrogen sulfide (NaHS) solution on experimental colitis. Colitis was induced by 2% dextran sulfate sodium (DSS) in the drinking water of C57BL/6 mice for 7 days. Some animal groups drank Harkány thermal spring water or water supplemented with 21.68 mg/L NaHS. General signs of colitis, myeloperoxidase (MPO) enzyme activity of colon samples, histological features of colitis and function of the enteric nervous system were assessed. Oral administration of Harkány thermal spring water significantly attenuated general signs of colitis, MPO enzyme activity of colon samples and detrimental effect of colitis on the function of the enteric nervous system, but not histological signs of colitis. These findings could be reproduced using NaHS solution with additional significantly diminished histological damage. We conclude that oral treatment with Harkány thermal spring water relieves various aspects of DSS-evoked colitis in mice. This effect is most likely to be mediated by hydrogen sulfide content of the Harkány water. Our data might promote complementary utilization of sulfurous thermal spring water in the therapy of inflammatory bowel disease.
The present study investigates the effect of oral consumption of hydrogen sulfide-containing Hark... more The present study investigates the effect of oral consumption of hydrogen sulfide-containing Harkány thermal spring water, as well as sodium hydrogen sulfide (NaHS) solution on experimental colitis. Colitis was induced by 2% dextran sulfate sodium (DSS) in the drinking water of C57BL/6 mice for 7 days. Some animal groups drank Harkány thermal spring water or water supplemented with 21.68 mg/L NaHS. General signs of colitis, myeloperoxidase (MPO) enzyme activity of colon samples, histological features of colitis and function of the enteric nervous system were assessed. Oral administration of Harkány thermal spring water significantly attenuated general signs of colitis, MPO enzyme activity of colon samples and detrimental effect of colitis on the function of the enteric nervous system, but not histological signs of colitis. These findings could be reproduced using NaHS solution with additional significantly diminished histological damage. We conclude that oral treatment with Harkány thermal spring water relieves various aspects of DSS-evoked colitis in mice. This effect is most likely to be mediated by hydrogen sulfide content of the Harkány water. Our data might promote complementary utilization of sulfurous thermal spring water in the therapy of inflammatory bowel disease.
A neurogenic component has been suggested to play a pivotal role in a range of inflammatory/immun... more A neurogenic component has been suggested to play a pivotal role in a range of inflammatory/immune diseases. Mustard oil (allyl-isothiocyanate) has been used in studies of inflammation to mediate neurogenic vasodilatation and oedema in rodent skin. The aim of the present study was to analyse mustard oil-induced oedema and neutrophil accumulation in the mouse ear focussing on the roles of neurokinin 1 (NK 1 ) and vanilloid (TRPV1) receptors using normal (BALB/c, C57BL/6) as well as NK 1 and TRPV1 receptor knockout mice. A single or double treatment of 1% mustard oil on the BALB/c mouse ear induced ear oedema with responses diminished by 6 h. However a 25-30% increase in ear thickness was maintained by the hourly reapplication of mustard oil. Desensitisation of sensory nerves with capsaicin, or the NK 1 receptor antagonist SR140333, inhibited oedema but only in the first 3 h. Neutrophil accumulation in response to mustard oil was inhibited neither by SR140333 nor capsaicin pre-treatment. An activating dose of capsaicin (2.5%) induced a large oedema in C57BL/6 wild-type mice that was minimal in TRPV1 receptor knockout mice. By comparison, mustard oil generated ear swelling was inhibited by SR140333 in wildtype and TRPV1 knockout mice. Repeated administration of mustard oil maintained 35% oedema in TRPV1 knockout animals and the lack of TRPV1 receptors did not alter the leukocyte accumulation. In contrast repeated treatment caused about 20% ear oedema in Sv129؉C57BL/6 wild-type mice but the absence of NK 1 receptors significantly decreased the response. Neutrophil accumulation showed similar values in both groups.
Proceedings of the National Academy of Sciences, 2009
We have shown that somatostatin released from activated capsaicin-sensitive nociceptive nerve end... more We have shown that somatostatin released from activated capsaicin-sensitive nociceptive nerve endings during inflammatory processes elicits systemic anti-inflammatory and analgesic effects. With the help of somatostatin receptor subtype 4 gene-deleted mice (sst(4)(-/-)), we provide here several lines of evidence that this receptor has a protective role in a variety of inflammatory disease models; several symptoms are more severe in the sst(4) knockout animals than in their wild-type counterparts. Acute carrageenan-induced paw edema and mechanical hyperalgesia, inflammatory pain in the early phase of adjuvant-evoked chronic arthritis, and oxazolone-induced delayed-type hypersensitivity reaction in the skin are much greater in mice lacking the sst(4) receptor. Airway inflammation and consequent bronchial hyperreactivity elicited by intranasal lipopolysaccharide administration are also markedly enhanced in sst(4) knockouts, including increased perivascular/peribronchial edema, neutrophil/macrophage infiltration, mucus-producing goblet cell hyperplasia, myeloperoxidase activity, and IL-1beta, TNF-alpha, and IFN-gamma expression in the inflamed lung. It is concluded that during these inflammatory conditions the released somatostatin has pronounced counterregulatory effects through sst(4) receptor activation. Thus, this receptor is a promising novel target for developing anti-inflammatory, analgesic, and anti-asthmatic drugs.
ABSTRACT Capsaicin-sensitive sensory neurons express several ion channels of the TRP family, such... more ABSTRACT Capsaicin-sensitive sensory neurons express several ion channels of the TRP family, such as transient receptor potential ankyrin 1 (TRPA1) receptors. TRPA1 can be activated by several chemical stimuli, such as allylisothiocyanate (AITC) or cinnamaldehyde resulting in the release of inflammatory neuropeptides, e.g. calcitonin gene-related peptide (CGRP) [1]. Recently, the gaseous mediator hydrogen sulfide (H2S) was suggested to have effect on capsaicin-sensitive sensory neurons acting via TRPA1 receptors. Microcirculatory changes in the mouse ear and hind paw have been investigated in this study. Balb/c, C57BL/6, TRPA1 KO and TRPV1 KO mice (20-30g) were treated with sodium hydrogen sulfide (NaHS) or AITC. Ipsilateral ears of the animals were treated with 2% AITC or 5% NaHS. Contralateral ears received respective vehicles. Balb/c mice received selective TRPA1 receptor antagonist HC-030031 (i.p., 30 or 100mg/kg). NaHS (0.5μmol/10 μL Tyrode) was injected s.c. into hind paws of C57BL/6 and TRPA1 KO mice. Skin blood flow was detected by laser Doppler imaging. AITC treatment of mouse ears led to 29.8±2.8% increase in blood flow. NaHS elevated cutaneous blood flow of the mouse ears by 61±4.5%. Effect of NaHS on microcirculation was ameliorated by HC-030031. Blood flow of TRPA1 KO mice showed significantly smaller increase in response to NaHS compared to the wild-type counterparts. Vasodilatation in TRPV1 KO animals did not differ from control. CGRP8-37 peptide antagonist of CGRP only partly inhibited the response. Intraplantar administration of NaHS elevated blood flow of murine hind paws by 34.1±2.8%. The plantar microcirculatory response to NaHS was unaffected by genetic lack of TRPA1 receptor or resiniferatoxin pretreatment. We conclude that NaHS-induced vasodilatation in the mouse ear is partly mediated by TRPA1 receptors, but is independent of sensory nerves in the skin of the hind paw.
Receptor Potential Vanilloid 1 (TRPV1) receptors/ion channels, which play an important regulatory... more Receptor Potential Vanilloid 1 (TRPV1) receptors/ion channels, which play an important regulatory role in inflammatory processes via the release of sensory neuropeptides. The aim of the present study was to investigate the role of TRPV1 receptors in endotoxin-induced airway inflammation and consequent bronchial hyperreactivity with functional, morphological and biochemical techniques using receptor gene-deficient mice. Inflammation was evoked by intranasal administration of E. coli lipopolysaccharide (60 µl, 167 µg/ml) in TRPV1 knockout (TRPV1 -/-) mice and their wild-type counterparts (TRPV1 +/+ ) 24 h before measurement.
Cross-talk between the nervous, endocrine and immune systems exists via regulator molecules, such... more Cross-talk between the nervous, endocrine and immune systems exists via regulator molecules, such as neuropeptides, hormones and cytokines. A number of neuropeptides have been implicated in the genesis of inflammation, such as tachykinins and calcitonin gene-related peptide. Development of their receptor antagonists could be a promising approach to anti-inflammatory pharmacotherapy. Anti-inflammatory neuropeptides, such as vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, a-melanocyte-stimulating hormone, urocortin, adrenomedullin, somatostatin, cortistatin, ghrelin, galanin and opioid peptides, are also released and act on their own receptors on the neurons as well as on different inflammatory and immune cells. The aim of the present review is to summarize the most prominent data of preclinical animal studies concerning the main pharmacological effects of ligands acting on the neuropeptide receptors. Promising therapeutic impacts of these compounds as potential candidates for the development of novel types of anti-inflammatory drugs are also discussed. G. NK3 receptor blockade prevents hyperalgesia and the associated spinal cord substance P release in monoarthritic rats. Neuropharmacology 2000; 39: 141-9.
Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive aff... more Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive afferents induce neurogenic inflammation via NK 1 , NK 2 and CGRP1 receptor activation. This study examines the role of capsaicin-sensitive fibres and sensory neuropeptides in endotoxininduced airway inflammation and consequent bronchial hyperreactivity with functional, morphological and biochemical techniques in mice. Carbachol-induced bronchoconstriction was measured with whole body plethysmography 24 h after intranasal lipopolysaccharide administration. SP and CGRP were determined with radioimmunoassay, myeloperoxidase activity with spectrophotometry, interleukin-1β with ELISA and histopathological changes with semiquantitative scoring from lung samples. Treatments with resiniferatoxin for selective destruction of capsaicinsensitive afferents, NK 1 antagonist SR 140333, NK 2 antagonist SR 48968, their combination, or CGRP1 receptor antagonist CGRP(8-37) were performed. Lipopolysaccharide significantly increased lung SP and CGRP concentrations, which was prevented by resiniferatoxin pretreatment. Resiniferatoxin-desensitization markedly enhanced inflammation, but decreased bronchoconstriction. CGRP(8-37) or combination of SR 140333 and SR 48968 diminished neutrophil accumulation, MPO levels and IL-1β production, airway hyperresponsiveness was inhibited only by SR 48968. This is the first evidence that capsaicin-sensitive afferents exert a protective role in endotoxin-induced airway inflammation, but contribute to increased bronchoconstriction. Activation of CGRP1 receptors or NK 1 + NK 2 receptors participate in granulocyte accumulation, but NK 2 receptors play predominant role in enhanced airway resistance.
Objective: The participation of sensory neurons and transient receptor potential vanilloid 1 (TRP... more Objective: The participation of sensory neurons and transient receptor potential vanilloid 1 (TRPV1) receptors in phorbol 12-myristate 13-acetate (PMA)-induced nerve-sensitizing effect was examined. Materials and methods: PMA dissolved in acetone and acetone were applied to the ears of TRPV1 receptor knockout and wild-type mice. Different groups of animals received ibuprofen, anti-interleukin-1 beta (IL-1β) antibody, resiniferatoxin (RTX) or capsaicin pretreatment. Ear thickness, myeloperoxidase activity and IL-1β content of the ears were determined. Histological evaluation was performed. Results: PMA exerted potentiating action on contralateral acetone-induced ear oedema, which was inhibited by ibuprofen, topical capsaicin desensitization of the acetone-treated ear as well as by systemic RTX pretreatment. Neither the lack of TRPV1 receptors nor anti-IL-1β antibody prevented sensitizing effect. Conclusions: The TRPV1 receptor-independent potentiating action of PMA on contralateral acetone-induced ear oedema is mediated via capsaicin-sensitive afferents and prostanoids are involved. IL-1β is not essential in this process.
Substance P (SP) and calcitonin gene-related peptide (CGRP), released from capsaicin-sensitive se... more Substance P (SP) and calcitonin gene-related peptide (CGRP), released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation, while somatostatin exerts systemic anti-inflammatory actions. The aim of the present study was to investigate the release of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) and its effects on sensory neuropeptide release in vitro and acute neurogenic ear swelling in vivo. Capsaicin (10(-6) M) or electrical field stimulation (EFS; 40 V, 0.1 ms, 10 Hz, 120 s; 1200 impulses)-induced release of PACAP-38, SP, CGRP and somatostatin from isolated rat tracheae was measured with radioimmunoassay. Mustard oil-induced neurogenic inflammation in the mouse ear was determined with a micrometer and in the rat hind paw skin by the Evans Blue leakage technique. Capsaicin and EFS evoked 27% and more than twofold elevation of PACAP-38 release respectively, compared with the prestimulated basal values from isolated trachea preparation. Exogenously administered PACAP-38 (20-2000 nM) diminished both capsaicin- and EFS-evoked sensory neuropeptide release in a concentration-dependent manner. The maximal inhibitory effects of PACAP on capsaicin-induced substance P, CGRP and somatostatin release amounted to 75.4%, 73.3% and 90.0%, while EFS-evoked release of these peptides was 80.03%, 87.7% and 67.7%. In case of capsaicin stimulation the EC50 values for substance P, CGRP and somatostatin were 82.9 nM, 60.1 nM and 66.9 nM, respectively. When EFS was performed, these corresponding EC50 data were 92.1 nM, 67.8 nM and 20.9 nM. PACAP-38 (10, 100 and 1000 microg/kg i.p. in 200 microl volume) inhibited neurogenic ear swelling in the mouse. Furthermore, 100 microg/kg i.p. PACAP also significantly diminished mustard oil-evoked plasma protein extravasation in the rat skin. These results suggest that PACAP-38 is released from the stimulated peripheral terminals of capsaicin-sensitive afferents and it is able to inhibit the outflow of sensory neuropeptides. Based on this mechanism of action PACAP is also able to effectively diminish/abolish neurogenic inflammatory response in vivo after systemic administration.
Background and purpose: Substance P (SP) and calcitonin gene-related peptide (CGRP) released from... more Background and purpose: Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation; somatostatin exerts systemic anti-inflammatory actions presumably via sst 4 /sst 1 receptors. This study investigates the effects of a high affinity, sst 4 -selective, synthetic agonist, J-2156, on sensory neuropeptide release in vitro and inflammatory processes in vivo. Experimental approach: Electrically-induced SP, CGRP and somatostatin release from isolated rat tracheae was measured with radioimmunoassay. Mustard oil-induced neurogenic inflammation in rat hindpaw skin was determined by Evans blue leakage and in the mouse ear with micrometry. Dextran-, carrageenan-or bradykinin-induced non-neurogenic inflammation was examined with plethysmometry or Evans blue, respectively. Adjuvant-induced chronic arthritis was assessed by plethysmometry and histological scoring. Granulocyte accumulation was determined with myeloperoxidase assay and IL-1b with ELISA. Key results: J-2156 (10-2000 nM) diminished electrically-evoked neuropeptide release in a concentration-dependent manner. EC 50 for the inhibition of substance P, CGRP and somatostatin release were 11.6 nM, 14.3 nM and 110.7 nM, respectively. J-2156 (1-100 mg kg À1 i.p.) significantly, but not dose-dependently, inhibited neurogenic and non-neurogenic acute inflammatory processes and adjuvant-induced chronic oedema and arthritic changes. Endotoxin-evoked myeloperoxidase activity and IL-1b production in the lung, but not IL-1b-or zymosan-induced leukocyte accumulation in the skin were significantly diminished by J-2156. Conclusions and implications: J-2156 acting on sst 4 receptors inhibits neuropeptide release, vascular components of acute inflammatory processes, endotoxin-induced granulocyte accumulation and IL-1b synthesis in the lung and synovial and inflammatory cells in chronic arthritis. Therefore it might be a promising lead for the development of novel anti-inflammatory drugs.
It has been established in animals that somatostatin (SST) is released from pain-activated sensor... more It has been established in animals that somatostatin (SST) is released from pain-activated sensory nerve endings and exerts systemic antinociceptive and anti-inflammatory actions. The aim of this study was to investigate the changes of SST-like immunoreactivity (SST-LI) in human serum before, immediately after and 2 h after surgical operations. 25 patients were enrolled in the study. Laparoscopic cholecystectomy, abdominal wall hernia or inguinal hernia operations were performed under combined anesthesia. A 5-ml blood sample was drawn from each patient, the blood was centrifuged and the serum frozen. SST-LI was determined from the defrosted samples by radioimmunoassay. Abdominal surgical operationsinduced a significant increase of SST-LI in the serum. 2 h later it was restored in the cases of laparoscopic interventions but still remained elevated after hernia surgeries. In this human study we showed for the first time that surgical interventions elevate the endogenous SST-LI in human serum. It is assumed that the released SST is derived from the activated sensory nerves. Since antinociceptive and anti-inflammatory effects of neural SST have already been established in laboratory animals, we presume that this endogenous protective mechanism also operates in humans.
Hydrogen sulfide (H2S) is a toxic gas. It has been recognized that H2S evolving in biochemical re... more Hydrogen sulfide (H2S) is a toxic gas. It has been recognized that H2S evolving in biochemical reactions in living organisms has an important role in different physiologic processes. Nowadays, H2S is known as an endogenous messenger molecule. Natural sulfurous spring water has been proved beneficial in the therapy of diseases of the skin and other organs (Boros et al 2013). In vivo real-time detection of local H2S concentration is an important but challenging task.We developed a two-electrode amperometric cell for selective subcutaneous detection of H2S in anesthetized mice. The cell is a small size implantable gas sensor containing a platinum disc anode and a silver cathode. The selectivity is provided by a membrane permeable only by gases. There is a buffered reversible electrochemical mediator solution in an oxidized form inside the cell. As gaseous H2S penetrates into the cell the mediator is reduced, and +0.4 V versus the reference is employed on the platinum working electrode. The reduced mediator is oxidized on the anode surface. The current provides an analytical signal representing the concentration of H2S.Appropriate shape, size and membrane material were selected, and optimal working parameters--such as mediator concentration, pH and cell voltage--were determined in vitro. The lower limit of detection in the stirred sample solution at pH = 5.5 was as small as 9.4 × 10(-7) M and a dynamic concentration range of 0-6 × 10(-4) M could be achieved.The detecting surfaces of the cell were covered with freshly dissected mouse skin to test dermal H2S permeability. In other experiments, the cell was implanted subcutaneously in an anesthetized mouse and the animal was submerged in a buffer solution containing different concentrations of H2S so that the skin surface over the sensor was covered by the solution. Measurements of subcutaneous H2S concentration were taken. The experiments clearly proved that H2S diffuses through the skin of the live mouse.
The present study investigates the effect of oral consumption of hydrogen sulfide-containing Hark... more The present study investigates the effect of oral consumption of hydrogen sulfide-containing Harkány thermal spring water, as well as sodium hydrogen sulfide (NaHS) solution on experimental colitis. Colitis was induced by 2% dextran sulfate sodium (DSS) in the drinking water of C57BL/6 mice for 7 days. Some animal groups drank Harkány thermal spring water or water supplemented with 21.68 mg/L NaHS. General signs of colitis, myeloperoxidase (MPO) enzyme activity of colon samples, histological features of colitis and function of the enteric nervous system were assessed. Oral administration of Harkány thermal spring water significantly attenuated general signs of colitis, MPO enzyme activity of colon samples and detrimental effect of colitis on the function of the enteric nervous system, but not histological signs of colitis. These findings could be reproduced using NaHS solution with additional significantly diminished histological damage. We conclude that oral treatment with Harkány thermal spring water relieves various aspects of DSS-evoked colitis in mice. This effect is most likely to be mediated by hydrogen sulfide content of the Harkány water. Our data might promote complementary utilization of sulfurous thermal spring water in the therapy of inflammatory bowel disease.
The present study investigates the effect of oral consumption of hydrogen sulfide-containing Hark... more The present study investigates the effect of oral consumption of hydrogen sulfide-containing Harkány thermal spring water, as well as sodium hydrogen sulfide (NaHS) solution on experimental colitis. Colitis was induced by 2% dextran sulfate sodium (DSS) in the drinking water of C57BL/6 mice for 7 days. Some animal groups drank Harkány thermal spring water or water supplemented with 21.68 mg/L NaHS. General signs of colitis, myeloperoxidase (MPO) enzyme activity of colon samples, histological features of colitis and function of the enteric nervous system were assessed. Oral administration of Harkány thermal spring water significantly attenuated general signs of colitis, MPO enzyme activity of colon samples and detrimental effect of colitis on the function of the enteric nervous system, but not histological signs of colitis. These findings could be reproduced using NaHS solution with additional significantly diminished histological damage. We conclude that oral treatment with Harkány thermal spring water relieves various aspects of DSS-evoked colitis in mice. This effect is most likely to be mediated by hydrogen sulfide content of the Harkány water. Our data might promote complementary utilization of sulfurous thermal spring water in the therapy of inflammatory bowel disease.
A neurogenic component has been suggested to play a pivotal role in a range of inflammatory/immun... more A neurogenic component has been suggested to play a pivotal role in a range of inflammatory/immune diseases. Mustard oil (allyl-isothiocyanate) has been used in studies of inflammation to mediate neurogenic vasodilatation and oedema in rodent skin. The aim of the present study was to analyse mustard oil-induced oedema and neutrophil accumulation in the mouse ear focussing on the roles of neurokinin 1 (NK 1 ) and vanilloid (TRPV1) receptors using normal (BALB/c, C57BL/6) as well as NK 1 and TRPV1 receptor knockout mice. A single or double treatment of 1% mustard oil on the BALB/c mouse ear induced ear oedema with responses diminished by 6 h. However a 25-30% increase in ear thickness was maintained by the hourly reapplication of mustard oil. Desensitisation of sensory nerves with capsaicin, or the NK 1 receptor antagonist SR140333, inhibited oedema but only in the first 3 h. Neutrophil accumulation in response to mustard oil was inhibited neither by SR140333 nor capsaicin pre-treatment. An activating dose of capsaicin (2.5%) induced a large oedema in C57BL/6 wild-type mice that was minimal in TRPV1 receptor knockout mice. By comparison, mustard oil generated ear swelling was inhibited by SR140333 in wildtype and TRPV1 knockout mice. Repeated administration of mustard oil maintained 35% oedema in TRPV1 knockout animals and the lack of TRPV1 receptors did not alter the leukocyte accumulation. In contrast repeated treatment caused about 20% ear oedema in Sv129؉C57BL/6 wild-type mice but the absence of NK 1 receptors significantly decreased the response. Neutrophil accumulation showed similar values in both groups.
Proceedings of the National Academy of Sciences, 2009
We have shown that somatostatin released from activated capsaicin-sensitive nociceptive nerve end... more We have shown that somatostatin released from activated capsaicin-sensitive nociceptive nerve endings during inflammatory processes elicits systemic anti-inflammatory and analgesic effects. With the help of somatostatin receptor subtype 4 gene-deleted mice (sst(4)(-/-)), we provide here several lines of evidence that this receptor has a protective role in a variety of inflammatory disease models; several symptoms are more severe in the sst(4) knockout animals than in their wild-type counterparts. Acute carrageenan-induced paw edema and mechanical hyperalgesia, inflammatory pain in the early phase of adjuvant-evoked chronic arthritis, and oxazolone-induced delayed-type hypersensitivity reaction in the skin are much greater in mice lacking the sst(4) receptor. Airway inflammation and consequent bronchial hyperreactivity elicited by intranasal lipopolysaccharide administration are also markedly enhanced in sst(4) knockouts, including increased perivascular/peribronchial edema, neutrophil/macrophage infiltration, mucus-producing goblet cell hyperplasia, myeloperoxidase activity, and IL-1beta, TNF-alpha, and IFN-gamma expression in the inflamed lung. It is concluded that during these inflammatory conditions the released somatostatin has pronounced counterregulatory effects through sst(4) receptor activation. Thus, this receptor is a promising novel target for developing anti-inflammatory, analgesic, and anti-asthmatic drugs.
ABSTRACT Capsaicin-sensitive sensory neurons express several ion channels of the TRP family, such... more ABSTRACT Capsaicin-sensitive sensory neurons express several ion channels of the TRP family, such as transient receptor potential ankyrin 1 (TRPA1) receptors. TRPA1 can be activated by several chemical stimuli, such as allylisothiocyanate (AITC) or cinnamaldehyde resulting in the release of inflammatory neuropeptides, e.g. calcitonin gene-related peptide (CGRP) [1]. Recently, the gaseous mediator hydrogen sulfide (H2S) was suggested to have effect on capsaicin-sensitive sensory neurons acting via TRPA1 receptors. Microcirculatory changes in the mouse ear and hind paw have been investigated in this study. Balb/c, C57BL/6, TRPA1 KO and TRPV1 KO mice (20-30g) were treated with sodium hydrogen sulfide (NaHS) or AITC. Ipsilateral ears of the animals were treated with 2% AITC or 5% NaHS. Contralateral ears received respective vehicles. Balb/c mice received selective TRPA1 receptor antagonist HC-030031 (i.p., 30 or 100mg/kg). NaHS (0.5μmol/10 μL Tyrode) was injected s.c. into hind paws of C57BL/6 and TRPA1 KO mice. Skin blood flow was detected by laser Doppler imaging. AITC treatment of mouse ears led to 29.8±2.8% increase in blood flow. NaHS elevated cutaneous blood flow of the mouse ears by 61±4.5%. Effect of NaHS on microcirculation was ameliorated by HC-030031. Blood flow of TRPA1 KO mice showed significantly smaller increase in response to NaHS compared to the wild-type counterparts. Vasodilatation in TRPV1 KO animals did not differ from control. CGRP8-37 peptide antagonist of CGRP only partly inhibited the response. Intraplantar administration of NaHS elevated blood flow of murine hind paws by 34.1±2.8%. The plantar microcirculatory response to NaHS was unaffected by genetic lack of TRPA1 receptor or resiniferatoxin pretreatment. We conclude that NaHS-induced vasodilatation in the mouse ear is partly mediated by TRPA1 receptors, but is independent of sensory nerves in the skin of the hind paw.
Receptor Potential Vanilloid 1 (TRPV1) receptors/ion channels, which play an important regulatory... more Receptor Potential Vanilloid 1 (TRPV1) receptors/ion channels, which play an important regulatory role in inflammatory processes via the release of sensory neuropeptides. The aim of the present study was to investigate the role of TRPV1 receptors in endotoxin-induced airway inflammation and consequent bronchial hyperreactivity with functional, morphological and biochemical techniques using receptor gene-deficient mice. Inflammation was evoked by intranasal administration of E. coli lipopolysaccharide (60 µl, 167 µg/ml) in TRPV1 knockout (TRPV1 -/-) mice and their wild-type counterparts (TRPV1 +/+ ) 24 h before measurement.
Cross-talk between the nervous, endocrine and immune systems exists via regulator molecules, such... more Cross-talk between the nervous, endocrine and immune systems exists via regulator molecules, such as neuropeptides, hormones and cytokines. A number of neuropeptides have been implicated in the genesis of inflammation, such as tachykinins and calcitonin gene-related peptide. Development of their receptor antagonists could be a promising approach to anti-inflammatory pharmacotherapy. Anti-inflammatory neuropeptides, such as vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, a-melanocyte-stimulating hormone, urocortin, adrenomedullin, somatostatin, cortistatin, ghrelin, galanin and opioid peptides, are also released and act on their own receptors on the neurons as well as on different inflammatory and immune cells. The aim of the present review is to summarize the most prominent data of preclinical animal studies concerning the main pharmacological effects of ligands acting on the neuropeptide receptors. Promising therapeutic impacts of these compounds as potential candidates for the development of novel types of anti-inflammatory drugs are also discussed. G. NK3 receptor blockade prevents hyperalgesia and the associated spinal cord substance P release in monoarthritic rats. Neuropharmacology 2000; 39: 141-9.
Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive aff... more Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive afferents induce neurogenic inflammation via NK 1 , NK 2 and CGRP1 receptor activation. This study examines the role of capsaicin-sensitive fibres and sensory neuropeptides in endotoxininduced airway inflammation and consequent bronchial hyperreactivity with functional, morphological and biochemical techniques in mice. Carbachol-induced bronchoconstriction was measured with whole body plethysmography 24 h after intranasal lipopolysaccharide administration. SP and CGRP were determined with radioimmunoassay, myeloperoxidase activity with spectrophotometry, interleukin-1β with ELISA and histopathological changes with semiquantitative scoring from lung samples. Treatments with resiniferatoxin for selective destruction of capsaicinsensitive afferents, NK 1 antagonist SR 140333, NK 2 antagonist SR 48968, their combination, or CGRP1 receptor antagonist CGRP(8-37) were performed. Lipopolysaccharide significantly increased lung SP and CGRP concentrations, which was prevented by resiniferatoxin pretreatment. Resiniferatoxin-desensitization markedly enhanced inflammation, but decreased bronchoconstriction. CGRP(8-37) or combination of SR 140333 and SR 48968 diminished neutrophil accumulation, MPO levels and IL-1β production, airway hyperresponsiveness was inhibited only by SR 48968. This is the first evidence that capsaicin-sensitive afferents exert a protective role in endotoxin-induced airway inflammation, but contribute to increased bronchoconstriction. Activation of CGRP1 receptors or NK 1 + NK 2 receptors participate in granulocyte accumulation, but NK 2 receptors play predominant role in enhanced airway resistance.
Objective: The participation of sensory neurons and transient receptor potential vanilloid 1 (TRP... more Objective: The participation of sensory neurons and transient receptor potential vanilloid 1 (TRPV1) receptors in phorbol 12-myristate 13-acetate (PMA)-induced nerve-sensitizing effect was examined. Materials and methods: PMA dissolved in acetone and acetone were applied to the ears of TRPV1 receptor knockout and wild-type mice. Different groups of animals received ibuprofen, anti-interleukin-1 beta (IL-1β) antibody, resiniferatoxin (RTX) or capsaicin pretreatment. Ear thickness, myeloperoxidase activity and IL-1β content of the ears were determined. Histological evaluation was performed. Results: PMA exerted potentiating action on contralateral acetone-induced ear oedema, which was inhibited by ibuprofen, topical capsaicin desensitization of the acetone-treated ear as well as by systemic RTX pretreatment. Neither the lack of TRPV1 receptors nor anti-IL-1β antibody prevented sensitizing effect. Conclusions: The TRPV1 receptor-independent potentiating action of PMA on contralateral acetone-induced ear oedema is mediated via capsaicin-sensitive afferents and prostanoids are involved. IL-1β is not essential in this process.
Substance P (SP) and calcitonin gene-related peptide (CGRP), released from capsaicin-sensitive se... more Substance P (SP) and calcitonin gene-related peptide (CGRP), released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation, while somatostatin exerts systemic anti-inflammatory actions. The aim of the present study was to investigate the release of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) and its effects on sensory neuropeptide release in vitro and acute neurogenic ear swelling in vivo. Capsaicin (10(-6) M) or electrical field stimulation (EFS; 40 V, 0.1 ms, 10 Hz, 120 s; 1200 impulses)-induced release of PACAP-38, SP, CGRP and somatostatin from isolated rat tracheae was measured with radioimmunoassay. Mustard oil-induced neurogenic inflammation in the mouse ear was determined with a micrometer and in the rat hind paw skin by the Evans Blue leakage technique. Capsaicin and EFS evoked 27% and more than twofold elevation of PACAP-38 release respectively, compared with the prestimulated basal values from isolated trachea preparation. Exogenously administered PACAP-38 (20-2000 nM) diminished both capsaicin- and EFS-evoked sensory neuropeptide release in a concentration-dependent manner. The maximal inhibitory effects of PACAP on capsaicin-induced substance P, CGRP and somatostatin release amounted to 75.4%, 73.3% and 90.0%, while EFS-evoked release of these peptides was 80.03%, 87.7% and 67.7%. In case of capsaicin stimulation the EC50 values for substance P, CGRP and somatostatin were 82.9 nM, 60.1 nM and 66.9 nM, respectively. When EFS was performed, these corresponding EC50 data were 92.1 nM, 67.8 nM and 20.9 nM. PACAP-38 (10, 100 and 1000 microg/kg i.p. in 200 microl volume) inhibited neurogenic ear swelling in the mouse. Furthermore, 100 microg/kg i.p. PACAP also significantly diminished mustard oil-evoked plasma protein extravasation in the rat skin. These results suggest that PACAP-38 is released from the stimulated peripheral terminals of capsaicin-sensitive afferents and it is able to inhibit the outflow of sensory neuropeptides. Based on this mechanism of action PACAP is also able to effectively diminish/abolish neurogenic inflammatory response in vivo after systemic administration.
Background and purpose: Substance P (SP) and calcitonin gene-related peptide (CGRP) released from... more Background and purpose: Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation; somatostatin exerts systemic anti-inflammatory actions presumably via sst 4 /sst 1 receptors. This study investigates the effects of a high affinity, sst 4 -selective, synthetic agonist, J-2156, on sensory neuropeptide release in vitro and inflammatory processes in vivo. Experimental approach: Electrically-induced SP, CGRP and somatostatin release from isolated rat tracheae was measured with radioimmunoassay. Mustard oil-induced neurogenic inflammation in rat hindpaw skin was determined by Evans blue leakage and in the mouse ear with micrometry. Dextran-, carrageenan-or bradykinin-induced non-neurogenic inflammation was examined with plethysmometry or Evans blue, respectively. Adjuvant-induced chronic arthritis was assessed by plethysmometry and histological scoring. Granulocyte accumulation was determined with myeloperoxidase assay and IL-1b with ELISA. Key results: J-2156 (10-2000 nM) diminished electrically-evoked neuropeptide release in a concentration-dependent manner. EC 50 for the inhibition of substance P, CGRP and somatostatin release were 11.6 nM, 14.3 nM and 110.7 nM, respectively. J-2156 (1-100 mg kg À1 i.p.) significantly, but not dose-dependently, inhibited neurogenic and non-neurogenic acute inflammatory processes and adjuvant-induced chronic oedema and arthritic changes. Endotoxin-evoked myeloperoxidase activity and IL-1b production in the lung, but not IL-1b-or zymosan-induced leukocyte accumulation in the skin were significantly diminished by J-2156. Conclusions and implications: J-2156 acting on sst 4 receptors inhibits neuropeptide release, vascular components of acute inflammatory processes, endotoxin-induced granulocyte accumulation and IL-1b synthesis in the lung and synovial and inflammatory cells in chronic arthritis. Therefore it might be a promising lead for the development of novel anti-inflammatory drugs.
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Papers by Gábor Pozsgai