Tumor necrosis factor-alpha (TNF-a) is a principal mediator in pro-inflammatory processes that in... more Tumor necrosis factor-alpha (TNF-a) is a principal mediator in pro-inflammatory processes that involve necrosis, apoptosis and proliferation. Experimental and clinical evidence demonstrate that peripheral nerve injury results in activation and morphological changes of microglial cells in the spinal cord. These adjustments occur in order to initiate an inflammatory cascade in response to the damage. Between the agents involved in this reaction, TNF-a is recognized as a key player in this process as it not only modulates lesion formation, but also because it is suggested to induce nociceptive signals. Nowadays, even though the function of TNF-a in inflammation and pain production seems to be generally accepted, diverse sources of literature point to different pathways and outcomes. In this review, we systematically searched and reviewed original articles from the past 10 years on animal models of peripheral nervous injury describing TNF-a expression in neural tissue and pain behavior.
People interested in the research are advised to contact the author for the final version of the ... more People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Neuromodulation: Technology at the Neural Interface, 2020
We aimed to investigate the efficacy of new subperception stimulation paradigms including 1.2 kHz... more We aimed to investigate the efficacy of new subperception stimulation paradigms including 1.2 kHz‐high‐frequency stimulation (HFS) and advanced‐HFS field‐shaping algorithm (dorsal horn HFS [DHHFS]) in refractory cases which initially benefited from conventional spinal cord stimulation (SCS) and lost the effect throughout time.
Neurotomies were one of the first procedures performed in the field of functional neurosurgery. M... more Neurotomies were one of the first procedures performed in the field of functional neurosurgery. Microstimulators and microscopes facilitate the performance of neurotomies to treat focal spasticity. This report shows how three different consecutive neurotomies were performed in one patient with chronic left upper/lower extremity spasticity. A 65-year-old male with intractable epilepsy underwent a right temporal lobectomy for seizure control. Postoperatively, he developed left upper/lower extremity spasticity attributed to a postoperative right internal capsule infarct. The severe spasticity persisted despite the administration of conventional drugs, rehabilitation efforts, and botulinic toxin injections. Three sequential selective neurotomies (e.g., spinal, median, and foot common flexor nerves) were next performed. Postoperatively, the neurotomies resulted in significant symptomatic long-term improvement, 6 years after spinal neurotomy, 7 years after median neurotomy, and 9 years af...
Anticoagulant prophylaxis for preventing VTE is a world wide established procedure in hip and kne... more Anticoagulant prophylaxis for preventing VTE is a world wide established procedure in hip and knee replacement surgery, as well as in the treatment of femoral neck fractures. Different guidelines are available in literature with quite different recommendations. None of them is a multydisciplinary effort as the one presented. The Italian Society for Studies on Haemostasis and Thrombosis (SISET), the Italian Society of Orthopaedics and Traumatology (SIOT),the association of Orthopaedic Traumatology of Italian Hospitals (OTODI) together with the Italian Society of Anesthesia,Analgesia,Resuscitation and Intensive Care (SIAARTI) have set down easy and quick suggestions for TEV prophylaxis in hip and knee surgery as well as in femoral neck fracture treatment. This intersociety consensus statement aims at simplifying the grading system reported in the literature, and its goal is to favour its clinical application. Special focuses have been also pointed toward fragile patients and on those patients at high risk of bleeding or receiving chronic antiplatelet and Vitamin K antagonists treatment. A special chapter have been dedicated to regional anaesthesia and TEV prophylaxis.
The contemporary debate about development based on natural resources has existed since the 1990s.... more The contemporary debate about development based on natural resources has existed since the 1990s. Numerous academic studies conducted in that decade called attention to the relationship between 113 F. de Castro et al. (eds.
Estimate the effects of methylprednisolone (MP) administration and olfactory bulb (OB) implantati... more Estimate the effects of methylprednisolone (MP) administration and olfactory bulb (OB) implantation independently and in combination after a spinal trauma model in Wistar rats, evaluated with BBB scale and CBS with remark of inclined plane test and Tarlov scale. Thirty adult rats were divided into six different groups, evaluated before trauma, one day post-surgery and weekly up to six weeks post-lesion. Group A (control); group B (sham) laminectomy without lesion; group C (SCI) lesion only; group D (MP) SCI and MP; group E (OB) SCI and OB implantation; group F (MP/OB) SCI and both therapeutics. Intragroup data at three weeks showed evident significance in groups D, E and F for Tarlov (p = 0.001) and BBB (p < 0.01); groups C, D, E and F for CBS (p < 0.05); and only group D with inclined plane (p < 0.05). On the sixth week differences were present in groups C, D, E, and F for Tarlov, BBB and CBS (p < 0.001); and C and F for inclined plane (p < 0.05). For intergroup analysis any treatment showed differences with Tarlov scale; for BBB and inclined plane, statistical differences were evident in groups E and F; and for CBS only in group F (p < 0.05). Real effects of MP are obtained at immediate follow-up, without notorious augmentation after time. OB improvement is achieved only after weeks. None of these therapies used independently achieve a constant and sustained improvement. Combined treatments were more effective and reached higher functional levels for longer periods of time.
Neuromodulation: Technology at the Neural Interface, 2009
Objective. Evaluate the possible decrease of chemically induced perseverative behavior in rats af... more Objective. Evaluate the possible decrease of chemically induced perseverative behavior in rats after electrical stimulation at different frequencies in the thalamic reticular nucleus. Material and Methods. A total of 28 male rats were divided in four groups: control, sham, OFF stimulation, and ON stimulation (450 msec, 1 V, 6 and 120 Hz) that underwent the administration of saline solution and 8-OH-DPAT. The animals were evaluated in a T-maze model in which three choices or more in the same branch are considered as perseverative. Intragroup analysis was done through paired T-student and intergroup analysis through an ANOVA test. Results. The numbers of perseverations mean for the control group were 1.3 before and 1.4 post saline solution injections. Sham group mean of 1.3 pre and 3.4 post 8-OH-DPAT administration; OFF stimulation group 1.1 pre and 3.3 post 8-OH-DPAT administration; and for ON stimulation 1.1 pre and 1.9 post 8-OH-DPAT administration for stimulation at low frequency (6 Hz) and 3.4 at high frequency (120 Hz). Evident intergroup statistical differences were shown (p < 0.01). Conclusions. Electrical stimulation with the low-frequency group was the only group that after manipulation with 8-OH-DPAT showed a decrease in perseverative behavior, even close to baseline.
Spastic diplegia is present in three-fourths of children with cerebral palsy, interfering with ga... more Spastic diplegia is present in three-fourths of children with cerebral palsy, interfering with gait and frequently accompanied by severe pain. The authors report the case of a 28-year-old woman with history of perinatal hypoxia, who presented with cerebral palsy and severe spastic diplegia (Ashworth Scale Score 4, Tardieu Scale Score 5) and was confined to a wheelchair. She complained of pain in the left hip and knee with mixed neuropathic and somatic components. She consistently rated pain intensity as 10 of 10 on a visual analog scale, and her symptoms were resistant to multiple treatments. The patient underwent selective bilateral adductor myotomies and the implantation of an infusion pump for intrathecal lidocaine application. Postoperative control of pain and spasticity was dramatic (scores of 0 on the Ashworth, Tardieu, and visual analog scales) and persisted throughout a follow-up period of 36 months. This is the first report in the literature of combined selective neurotomie...
The aim of this study was to systematically review the data published on deep brain stimulation (... more The aim of this study was to systematically review the data published on deep brain stimulation (DBS) of the globus pallidus internus (GPi) in Parkinson's disease (PD), and to determine its efficacy and optimal stimulation parameters. Only 22 of 4,648 articles fulfilled the inclusion and exclusion criteria of the study. The data were analysed using the Wilcoxon test. For 327 patients who underwent GPi-DBS, the preoperative baseline Unified Parkinson's Disease Rating Scale (UPDRS) score, off-medication, mean was 52.7 (range 26.5-77.2). The postoperative UPDRS score, off-medication/on-stimulation, mean was 33.7 (range 18.7-46.2). The delta mean (the difference in mean UPDRS score between baseline and maximum follow-up) was 19.1 (range À2.2 to 36.5) (p < 0.001). When the electrical parameters were compared against the delta UPDRS score, the analysis showed that only frequency was correlated with motor improvement (R 2 = 0.42, p < 0.05). Thus, GPi-DBS is a highly effective target for neuromodulation in PD. However, we found that significant clinical improvement (>50% delta UPDRS score) in PD is achieved at an amplitude of between 2.0 V and 3.5 V, a pulse-width between 75 ls and 300 ls and a frequency between 100 Hz and 190 Hz.
Objective: To perform a preliminary study on the effects and safety of bilateral cingulotomy and ... more Objective: To perform a preliminary study on the effects and safety of bilateral cingulotomy and anterior capsulotomy in patients with aggressive behavior. Patients and Methods: Twenty-three psychiatric patients showing aggressive behavior refractory to conventional treatment were initially evaluated. The subjects were clinically selected using the Overt Aggression Scale (OAS) and the Global Assessment of Functioning Scale (GAF). Each case was carefully reviewed by the Ethics Committee of Mexico's General Hospital. Once selection criteria were met, stereotactic lesions were made using radiofrequency on the anterior limb of the internal capsule and supragenual cingulum. Statistical differences were evaluated with a Wilcoxon test at 6 months and at 4 years. Results: Ten patients underwent surgery. Their OAS and GAF scores decreased after the procedure at the 6-month (p < 0.05) and at the 4-year (p = 0.068) follow-up. Four patients showed mild and transitory postsurgical compli...
European Journal of Drug Metabolism and Pharmacokinetics, 1997
The metabolism of GVI50013X was studied in vitro using washed liver microsomes and liver tissue s... more The metabolism of GVI50013X was studied in vitro using washed liver microsomes and liver tissue slices from different species. This work was carried out in order to compare the metabolite profiles resulting from incubation of GVI50013X with human, rat, dog and rabbit liver microsomes and those from rat, rabbit and human liver tissue slices. This compound was found to be converted to at least 8 metabolites by rat and human liver microsomes. In rabbit liver microsomes, the three metabolites M4, M7 and M8, and in dog liver microsomes metabolite MI, were not detected. The main metabolites, M2, M5 and M6, were present in human, rat and rabbit liver tissue slices, while the three metabolites M3, M4 and M8 and metabolite MI were not detected in rabbit and rat liver tissue slices, respectively. In rat liver tissue slices, the major metabolites plus five minor metabolites, one sulphate conjugate of a monohydroxylated, three trihydroxylated: and one dihydroxylated were identified based on HPLC retention time and thermospray-mass spectrometry data. Quantitative species differences among rat, dog, rabbit and human were observed, while qualitative differences only between rabbit and other species were detected.
Objective: Stereotaxic lesions of the orbitofrontal-thalamic system, specifically the thalamic re... more Objective: Stereotaxic lesions of the orbitofrontal-thalamic system, specifically the thalamic reticular nucleus (TRN), could be helpful to prevent perseverative behavior in rats produced by 8-OH-DPAT. Methods: Fifty rats were conditioned in a T-maze to measure the number of perseverations. Habituation was performed on days 1 and 2, baseline scores were obtained on day 3 and the final test was done on day 4 (chemical induction). Group I only received saline solution injection; group II was only submitted to 8-OH-DPAT; group III received pharmacological treatment with chlorimipramine (CMI) before 8-OH-DPAT administration; group IV and group V were submitted to stereotaxic bilateral lesions, one week before T-maze evaluation, in the TRN and orbitofrontal cortex (OFC), respectively and received 8-OH-DPAT administration. Results: No differences between groups were found at baseline on day 3 (p < 0.05). Significant differences were found between days 3 and 4 of evaluation only in group II (p < 0.01) and group V (p < 0.001). Differences between groups on day 4 were significant (p < 0.01). Conclusions: TRN lesions were as effective as CMI administration to prevent the 8-OH-DPAT action. OFC lesions failed to prevent the perseverative behavior.
ABSTRACT The present study focused on the relationship between the queen and work - ers in Acromy... more ABSTRACT The present study focused on the relationship between the queen and work - ers in Acromyrmex subterraneus brunneus colonies mediated by the possible transfer of substances from the fertile to the sterile caste. The queens were submitted to different situations of physical limitation, i.e., they were kept isolated in cages with holes that only permitted the entry of workers but left the queen isolated. A tracer (water-soluble dye) was applied to the pronotum and gaster of the queen and its dispersal among workers was analyzed. The results demonstrated that the minor sub caste (0.7-0.9 mm) passed on the dye through allogrooming and self-grooming, or transferred the dye through trophallaxis to the major sub caste (1.2-2.0 mm) when they were not in direct contact with the queen. These findings indicate the communication and probable transfer of substances from the queen to the workers, as well as a substance transfer between workers.
Tumor necrosis factor-alpha (TNF-a) is a principal mediator in pro-inflammatory processes that in... more Tumor necrosis factor-alpha (TNF-a) is a principal mediator in pro-inflammatory processes that involve necrosis, apoptosis and proliferation. Experimental and clinical evidence demonstrate that peripheral nerve injury results in activation and morphological changes of microglial cells in the spinal cord. These adjustments occur in order to initiate an inflammatory cascade in response to the damage. Between the agents involved in this reaction, TNF-a is recognized as a key player in this process as it not only modulates lesion formation, but also because it is suggested to induce nociceptive signals. Nowadays, even though the function of TNF-a in inflammation and pain production seems to be generally accepted, diverse sources of literature point to different pathways and outcomes. In this review, we systematically searched and reviewed original articles from the past 10 years on animal models of peripheral nervous injury describing TNF-a expression in neural tissue and pain behavior.
People interested in the research are advised to contact the author for the final version of the ... more People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Neuromodulation: Technology at the Neural Interface, 2020
We aimed to investigate the efficacy of new subperception stimulation paradigms including 1.2 kHz... more We aimed to investigate the efficacy of new subperception stimulation paradigms including 1.2 kHz‐high‐frequency stimulation (HFS) and advanced‐HFS field‐shaping algorithm (dorsal horn HFS [DHHFS]) in refractory cases which initially benefited from conventional spinal cord stimulation (SCS) and lost the effect throughout time.
Neurotomies were one of the first procedures performed in the field of functional neurosurgery. M... more Neurotomies were one of the first procedures performed in the field of functional neurosurgery. Microstimulators and microscopes facilitate the performance of neurotomies to treat focal spasticity. This report shows how three different consecutive neurotomies were performed in one patient with chronic left upper/lower extremity spasticity. A 65-year-old male with intractable epilepsy underwent a right temporal lobectomy for seizure control. Postoperatively, he developed left upper/lower extremity spasticity attributed to a postoperative right internal capsule infarct. The severe spasticity persisted despite the administration of conventional drugs, rehabilitation efforts, and botulinic toxin injections. Three sequential selective neurotomies (e.g., spinal, median, and foot common flexor nerves) were next performed. Postoperatively, the neurotomies resulted in significant symptomatic long-term improvement, 6 years after spinal neurotomy, 7 years after median neurotomy, and 9 years af...
Anticoagulant prophylaxis for preventing VTE is a world wide established procedure in hip and kne... more Anticoagulant prophylaxis for preventing VTE is a world wide established procedure in hip and knee replacement surgery, as well as in the treatment of femoral neck fractures. Different guidelines are available in literature with quite different recommendations. None of them is a multydisciplinary effort as the one presented. The Italian Society for Studies on Haemostasis and Thrombosis (SISET), the Italian Society of Orthopaedics and Traumatology (SIOT),the association of Orthopaedic Traumatology of Italian Hospitals (OTODI) together with the Italian Society of Anesthesia,Analgesia,Resuscitation and Intensive Care (SIAARTI) have set down easy and quick suggestions for TEV prophylaxis in hip and knee surgery as well as in femoral neck fracture treatment. This intersociety consensus statement aims at simplifying the grading system reported in the literature, and its goal is to favour its clinical application. Special focuses have been also pointed toward fragile patients and on those patients at high risk of bleeding or receiving chronic antiplatelet and Vitamin K antagonists treatment. A special chapter have been dedicated to regional anaesthesia and TEV prophylaxis.
The contemporary debate about development based on natural resources has existed since the 1990s.... more The contemporary debate about development based on natural resources has existed since the 1990s. Numerous academic studies conducted in that decade called attention to the relationship between 113 F. de Castro et al. (eds.
Estimate the effects of methylprednisolone (MP) administration and olfactory bulb (OB) implantati... more Estimate the effects of methylprednisolone (MP) administration and olfactory bulb (OB) implantation independently and in combination after a spinal trauma model in Wistar rats, evaluated with BBB scale and CBS with remark of inclined plane test and Tarlov scale. Thirty adult rats were divided into six different groups, evaluated before trauma, one day post-surgery and weekly up to six weeks post-lesion. Group A (control); group B (sham) laminectomy without lesion; group C (SCI) lesion only; group D (MP) SCI and MP; group E (OB) SCI and OB implantation; group F (MP/OB) SCI and both therapeutics. Intragroup data at three weeks showed evident significance in groups D, E and F for Tarlov (p = 0.001) and BBB (p < 0.01); groups C, D, E and F for CBS (p < 0.05); and only group D with inclined plane (p < 0.05). On the sixth week differences were present in groups C, D, E, and F for Tarlov, BBB and CBS (p < 0.001); and C and F for inclined plane (p < 0.05). For intergroup analysis any treatment showed differences with Tarlov scale; for BBB and inclined plane, statistical differences were evident in groups E and F; and for CBS only in group F (p < 0.05). Real effects of MP are obtained at immediate follow-up, without notorious augmentation after time. OB improvement is achieved only after weeks. None of these therapies used independently achieve a constant and sustained improvement. Combined treatments were more effective and reached higher functional levels for longer periods of time.
Neuromodulation: Technology at the Neural Interface, 2009
Objective. Evaluate the possible decrease of chemically induced perseverative behavior in rats af... more Objective. Evaluate the possible decrease of chemically induced perseverative behavior in rats after electrical stimulation at different frequencies in the thalamic reticular nucleus. Material and Methods. A total of 28 male rats were divided in four groups: control, sham, OFF stimulation, and ON stimulation (450 msec, 1 V, 6 and 120 Hz) that underwent the administration of saline solution and 8-OH-DPAT. The animals were evaluated in a T-maze model in which three choices or more in the same branch are considered as perseverative. Intragroup analysis was done through paired T-student and intergroup analysis through an ANOVA test. Results. The numbers of perseverations mean for the control group were 1.3 before and 1.4 post saline solution injections. Sham group mean of 1.3 pre and 3.4 post 8-OH-DPAT administration; OFF stimulation group 1.1 pre and 3.3 post 8-OH-DPAT administration; and for ON stimulation 1.1 pre and 1.9 post 8-OH-DPAT administration for stimulation at low frequency (6 Hz) and 3.4 at high frequency (120 Hz). Evident intergroup statistical differences were shown (p < 0.01). Conclusions. Electrical stimulation with the low-frequency group was the only group that after manipulation with 8-OH-DPAT showed a decrease in perseverative behavior, even close to baseline.
Spastic diplegia is present in three-fourths of children with cerebral palsy, interfering with ga... more Spastic diplegia is present in three-fourths of children with cerebral palsy, interfering with gait and frequently accompanied by severe pain. The authors report the case of a 28-year-old woman with history of perinatal hypoxia, who presented with cerebral palsy and severe spastic diplegia (Ashworth Scale Score 4, Tardieu Scale Score 5) and was confined to a wheelchair. She complained of pain in the left hip and knee with mixed neuropathic and somatic components. She consistently rated pain intensity as 10 of 10 on a visual analog scale, and her symptoms were resistant to multiple treatments. The patient underwent selective bilateral adductor myotomies and the implantation of an infusion pump for intrathecal lidocaine application. Postoperative control of pain and spasticity was dramatic (scores of 0 on the Ashworth, Tardieu, and visual analog scales) and persisted throughout a follow-up period of 36 months. This is the first report in the literature of combined selective neurotomie...
The aim of this study was to systematically review the data published on deep brain stimulation (... more The aim of this study was to systematically review the data published on deep brain stimulation (DBS) of the globus pallidus internus (GPi) in Parkinson's disease (PD), and to determine its efficacy and optimal stimulation parameters. Only 22 of 4,648 articles fulfilled the inclusion and exclusion criteria of the study. The data were analysed using the Wilcoxon test. For 327 patients who underwent GPi-DBS, the preoperative baseline Unified Parkinson's Disease Rating Scale (UPDRS) score, off-medication, mean was 52.7 (range 26.5-77.2). The postoperative UPDRS score, off-medication/on-stimulation, mean was 33.7 (range 18.7-46.2). The delta mean (the difference in mean UPDRS score between baseline and maximum follow-up) was 19.1 (range À2.2 to 36.5) (p < 0.001). When the electrical parameters were compared against the delta UPDRS score, the analysis showed that only frequency was correlated with motor improvement (R 2 = 0.42, p < 0.05). Thus, GPi-DBS is a highly effective target for neuromodulation in PD. However, we found that significant clinical improvement (>50% delta UPDRS score) in PD is achieved at an amplitude of between 2.0 V and 3.5 V, a pulse-width between 75 ls and 300 ls and a frequency between 100 Hz and 190 Hz.
Objective: To perform a preliminary study on the effects and safety of bilateral cingulotomy and ... more Objective: To perform a preliminary study on the effects and safety of bilateral cingulotomy and anterior capsulotomy in patients with aggressive behavior. Patients and Methods: Twenty-three psychiatric patients showing aggressive behavior refractory to conventional treatment were initially evaluated. The subjects were clinically selected using the Overt Aggression Scale (OAS) and the Global Assessment of Functioning Scale (GAF). Each case was carefully reviewed by the Ethics Committee of Mexico's General Hospital. Once selection criteria were met, stereotactic lesions were made using radiofrequency on the anterior limb of the internal capsule and supragenual cingulum. Statistical differences were evaluated with a Wilcoxon test at 6 months and at 4 years. Results: Ten patients underwent surgery. Their OAS and GAF scores decreased after the procedure at the 6-month (p < 0.05) and at the 4-year (p = 0.068) follow-up. Four patients showed mild and transitory postsurgical compli...
European Journal of Drug Metabolism and Pharmacokinetics, 1997
The metabolism of GVI50013X was studied in vitro using washed liver microsomes and liver tissue s... more The metabolism of GVI50013X was studied in vitro using washed liver microsomes and liver tissue slices from different species. This work was carried out in order to compare the metabolite profiles resulting from incubation of GVI50013X with human, rat, dog and rabbit liver microsomes and those from rat, rabbit and human liver tissue slices. This compound was found to be converted to at least 8 metabolites by rat and human liver microsomes. In rabbit liver microsomes, the three metabolites M4, M7 and M8, and in dog liver microsomes metabolite MI, were not detected. The main metabolites, M2, M5 and M6, were present in human, rat and rabbit liver tissue slices, while the three metabolites M3, M4 and M8 and metabolite MI were not detected in rabbit and rat liver tissue slices, respectively. In rat liver tissue slices, the major metabolites plus five minor metabolites, one sulphate conjugate of a monohydroxylated, three trihydroxylated: and one dihydroxylated were identified based on HPLC retention time and thermospray-mass spectrometry data. Quantitative species differences among rat, dog, rabbit and human were observed, while qualitative differences only between rabbit and other species were detected.
Objective: Stereotaxic lesions of the orbitofrontal-thalamic system, specifically the thalamic re... more Objective: Stereotaxic lesions of the orbitofrontal-thalamic system, specifically the thalamic reticular nucleus (TRN), could be helpful to prevent perseverative behavior in rats produced by 8-OH-DPAT. Methods: Fifty rats were conditioned in a T-maze to measure the number of perseverations. Habituation was performed on days 1 and 2, baseline scores were obtained on day 3 and the final test was done on day 4 (chemical induction). Group I only received saline solution injection; group II was only submitted to 8-OH-DPAT; group III received pharmacological treatment with chlorimipramine (CMI) before 8-OH-DPAT administration; group IV and group V were submitted to stereotaxic bilateral lesions, one week before T-maze evaluation, in the TRN and orbitofrontal cortex (OFC), respectively and received 8-OH-DPAT administration. Results: No differences between groups were found at baseline on day 3 (p < 0.05). Significant differences were found between days 3 and 4 of evaluation only in group II (p < 0.01) and group V (p < 0.001). Differences between groups on day 4 were significant (p < 0.01). Conclusions: TRN lesions were as effective as CMI administration to prevent the 8-OH-DPAT action. OFC lesions failed to prevent the perseverative behavior.
ABSTRACT The present study focused on the relationship between the queen and work - ers in Acromy... more ABSTRACT The present study focused on the relationship between the queen and work - ers in Acromyrmex subterraneus brunneus colonies mediated by the possible transfer of substances from the fertile to the sterile caste. The queens were submitted to different situations of physical limitation, i.e., they were kept isolated in cages with holes that only permitted the entry of workers but left the queen isolated. A tracer (water-soluble dye) was applied to the pronotum and gaster of the queen and its dispersal among workers was analyzed. The results demonstrated that the minor sub caste (0.7-0.9 mm) passed on the dye through allogrooming and self-grooming, or transferred the dye through trophallaxis to the major sub caste (1.2-2.0 mm) when they were not in direct contact with the queen. These findings indicate the communication and probable transfer of substances from the queen to the workers, as well as a substance transfer between workers.
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