It is currently known that in CNS the extracellular matrix is involved in synaptic stabilization ... more It is currently known that in CNS the extracellular matrix is involved in synaptic stabilization and limitation of synaptic plasticity. However, it has been reported that the treatment with chondroitinase following injury allows the formation of new synapses and increased plasticity and functional recovery. So, we hypothesize that some components of extracellular matrix may modulate synaptic transmission. To test this hypothesis we evaluated the effects of chondroitin sulphate (CS) on excitatory synaptic transmission, cellular excitability, and neuronal plasticity using extracellular recordings in the CA1 area of rat hippocampal slices. CS caused a reversible depression of evoked field excitatory postsynaptic potentials in a concentration-dependent manner. CS also reduced the population spike amplitude evoked after orthodromic stimulation but not when the population spikes were antidromically evoked; in this last case a potentiation was observed. CS also enhanced paired-pulse facilitation and long-term potentiation. Our study provides evidence that CS, a major component of the brain perineuronal net and extracellular matrix, has a function beyond the structural one, namely, the modulation of synaptic transmission and neuronal plasticity in the hippocampus.
Why adrenal chromaffin cells express various subtypes of voltage-dependent Ca 2+ channels and whe... more Why adrenal chromaffin cells express various subtypes of voltage-dependent Ca 2+ channels and whether a given channel is specialized to perform a specific function are puzzling and unanswered questions. In this study, we have used the L Ca 2+ channel activator FPL64176 (FPL) to test the hypothesis that enhanced Ca 2+ entry through this channel favors the inhibition of N and PQ channels in voltage-clamped bovine adrenal chromaffin cells. Using 2 mM Ca 2+ as charge carrier and under the perforated-patch configuration (PPC) of the patch-clamp technique, FPL caused a paradoxical inhibition of the whole-cell inward Ca 2+ current (I Ca ). Such inhibition turned on into an augmentation upon cell loading with EGTA-AM. Also, under the whole-cell configuration (WCC) of the patchclamp technique, FPL decreased I Ca in the absence of EGTA from the pipette solution and increased the current in its presence. Using 2 mM Ba 2+ as charge carrier, FPL augmented the Ba 2+ current under both recording conditions, WCC and PPC. FPL augmented the residual current remaining after blockade of N and PQ channels with ω-conotoxin MVIIC or by holding the membrane potential at −50 mV. The data support the view that Ca 2+ entering the cell through the lesser inactivating L channels serves to modulate the more inactivating N and PQ channels. They also suggest a close colocalization of L and N/PQ Ca 2+ channels. This kind of L channel specialization may be relevant to cell excitability, exocytosis, and cell survival mechanisms.
During fast superfusion of bovine chromaffin cells with normal Krebs-HEPES solution containing 2 ... more During fast superfusion of bovine chromaffin cells with normal Krebs-HEPES solution containing 2 mM Ca 2+ , pulses of 100 µM ACh or 100 mM K + of increasing duration (1-5 s) caused similar exocytosis of about 3-4 µC catecholamine. Depletion of endoplasmic reticulum (ER) Ca 2+ by pretreatment with 1 µM thapsigargin, 10 mM caffeine and 10 µM ryanodine more than halved the responses to ACh but did not affect the responses to K + responses. In these ER Ca 2+ -depleted cells the protonophore carbonylcyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) (20 µM given during the 5 s preceding each pulse) augmented the responses to ACh responses fourfold for all pulse durations applied (1-5 s) whereas responses to K + were potentiated twofold with 1 to 2 s pulses but were not affected with longer pulse durations. ACh pulses applied to fura-2-loaded cells evoked increases of bulk cytosolic [Ca 2+ ] ([Ca 2+ ] c ) that were substantially smaller than those elicited by K + pulses. Confocal microscopy of fluo-3-loaded cells showed that ACh pulses elicited discrete and more localized [Ca 2+ ] c elevations, whereas K + pulses produced higher [Ca 2+ ] c transients that spread out quickly throughout the cytosol. These results suggest that mitochondria sense the increase of local [Ca 2+ ] c elicited by ACh (that evokes firing of action potentials) much better than that induced by K + (that produces sustained cell depolarisation). This implies that mitochondria are more sensitive to the local [Ca 2+ ] c changes resulting from the physiological triggering of action potentials by ACh.
The Fourier duality is an elegant technique to obtain sampling formulas in Paley-Wiener spaces. I... more The Fourier duality is an elegant technique to obtain sampling formulas in Paley-Wiener spaces. In this paper it is proved that there exists an analogous of the Fourier duality technique in the setting of shift-invariant spaces. In fact, any shiftinvariant space V ϕ with a stable generator ϕ is the range space of a bounded oneto-one linear operator T between L 2 (0, 1) and L 2 (R). Thus, regular and irregular sampling formulas in V ϕ are obtained by transforming, via T , expansions in L 2 (0, 1) with respect to some appropriate Riesz bases.
In this paper we investigate approximation from shift-invariant spaces by using generalized sampl... more In this paper we investigate approximation from shift-invariant spaces by using generalized sampling formulas. These sampling formulas involve samples of filtered versions of the function itself. The considered systems include averaging samplers, and classical sampling of the function and its derivatives. Under appropriate hypotheses on the generator ϕ of the shift-invariant space and on the involved systems, we derive stable generalized sampling formulas in a shift-invariant subspace of L p (R n ). From these generalized sampling formulas we construct approximation schemes valid for smooth functions. The approximation order depends both on the order for which the Strang-Fix conditions are satisfied by ϕ, and on the largest order of the derivatives appearing in the systems if any.
Objectives: Heightened body awareness can be adaptive and maladaptive. Improving body awareness h... more Objectives: Heightened body awareness can be adaptive and maladaptive. Improving body awareness has been suggested as an approach for treating patients with conditions such as chronic pain, obesity and post-traumatic stress disorder. We assessed the psychometric quality of selected self-report measures and examined their items for underlying definitions of the construct.
1 The eects of lubeluzole (a neuroprotective benzothiazole derivative) and its (7) enantiomer R91... more 1 The eects of lubeluzole (a neuroprotective benzothiazole derivative) and its (7) enantiomer R91154 on whole-cell currents through Ca 2+ channels, with 10 mM Ba 2+ as charge carrier (I Ba ), have been studied in bovine and mouse voltage-clamped adrenal chroman cells. Currents generated by applying 50 ms depolarizing test pulses to 0 mV, from a holding potential of 780 mV, at 10 s intervals had an average magnitude of 1 nA. 2 Lubeluzole and R91154 blocked the peak I Ba of bovine chroman cells in a time and concentrationdependent manner; their IC 50 s were 1.94 mM for lubeluzole and 2.54 mM for R91154. In a current-voltage protocol, lubeluzole (3 mM) inhibited peak I Ba at all test potentials. However, no obvious shifts of the I-V curve were detected. 3 After 10 min exposure to 3 mM lubeluzole, the late current (measured at the end of the pulse) was inhibited more than the peak current. Upon wash out of the drug, the inactivation reversed ®rst and then the peak current recovered. 4 Blockade of peak current was greater at more depolarizing holding potentials (i.e. 35% at 7110 mV and 87% at 750 mV, after 10 min superfusion with lubeluzole). Inactivation of the current was pronounced at 7110 mV, decreased at 780 mV and did not occur at 750 mV. 5 Intracellular dialysis of bovine voltage-clamped chroman cells with 3 mM lubeluzole caused neither blockade nor inactivation of I Ba . The external application of 3 mM lubeluzole to those dialysed cells produced inhibition as well as inactivation of I Ba . 6 The eects of lubeluzole (3 mM) on I Ba in mouse chroman cells were similar to those in bovine chroman cells. At 780 mV holding potential, a pronounced inactivation of the current led to greater blockade of the late I Ba (66%) as compared with peak I Ba (46% after 10 min superfusion with lubeluzole). 7 In mouse chroman cells approximately half of the whole-cell I Ba was sensitive to 3 mM nifedipine (L-type Ca 2+ channels) and the other half to 3 mM o-conotoxin MVIIC (non-L-type Ca 2+ channels). In o-conotoxin MVIIC-treated cells, 3 mM lubeluzole caused little blockade and inactivation of I Ba . However in nifedipine-treated cells, lubeluzole caused a pronounced blockade and inactivation of I Ba that reversed upon wash out of the compound. 8 The results are compatible with the idea that lubeluzole preferentially blocks non-L-types of voltagedependent Ca 2+ channels expressed by bovine and mouse chroman cells. The higher concentrations of the compound also block L-type Ca 2+ channels. The mechanism of inhibition involves the access of lubeluzole to the open channel from the outside of the cell and promotion of its inactivation. The dierential blockade of Ca 2+ channel subtypes might contribute to the neuroprotective actions of lubeluzole (which exhibit stereoselectivity). However, in view of the lack of stereoselectivity in blocking Ca 2+ channels, this eect cannot be the only explanation for the protective activity of lubeluzole in stroke.
Background: Of the putative psychopathological endophenotypes in major depressive disorder (MDD),... more Background: Of the putative psychopathological endophenotypes in major depressive disorder (MDD), the anhedonic subtype is particularly well supported. Anhedonia is generally assumed to reflect aberrant motivation and reward responsivity. However, research has been limited by a lack of objective measures of reward motivation. We present the Effort-Expenditure for Rewards Task (EEfRT or ''effort''), a novel behavioral paradigm as a means of exploring effort-based decision-making in humans. Using the EEfRT, we test the hypothesis that effort-based decision-making is related to trait anhedonia.
Chronic use of cocaine is associated with a reduced density of dopaminergic D2 receptors in the s... more Chronic use of cocaine is associated with a reduced density of dopaminergic D2 receptors in the striatum, with negative consequences for cognitive control processes. Increasing evidence suggests that cognitive control is also affected in recreational cocaine consumers. This study aimed at linking these observations to dopaminergic malfunction by studying the spontaneous eyeblink rate (EBR), a marker of striatal dopaminergic functioning, in adult recreational users and a cocaine-free sample that was matched on age, race, gender, and personality traits. Correlation analyses show that EBR is significantly reduced in recreational users compared to cocaine-free controls, suggesting that cocaine use induces hypoactivity in the subcortical dopamine system. Citation: Colzato LS, van den Wildenberg WPM, Hommel B (2008) Reduced Spontaneous Eye Blink Rates in Recreational Cocaine Users: Evidence for Dopaminergic Hypoactivity. PLoS ONE 3(10): e3461.
Despite the abundance of evidence that human perception is penetrated by beliefs and expectations... more Despite the abundance of evidence that human perception is penetrated by beliefs and expectations, scientific research so far has entirely neglected the possible impact of religious background on attention. Here we show that Dutch Calvinists and atheists, brought up in the same country and culture and controlled for race, intelligence, sex, and age, differ with respect to the way they attend to and process the global and local features of complex visual stimuli: Calvinists attend less to global aspects of perceived events, which fits with the idea that people's attentional processing style reflects possible biases rewarded by their religious belief system. Citation: Colzato LS, van den Wildenberg WPM, Hommel B (2008) Losing the Big Picture: How Religion May Control Visual Attention. PLoS ONE 3(11): e3679.
Cocaine is Europe's second preferred recreational... more Cocaine is Europe's second preferred recreational drug after cannabis but very little is known about possible cognitive impairments in the upcoming type of recreational cocaine user (monthly consumption). We asked whether recreational use of cocaine impacts early attentional selection processes. Cocaine-free polydrug controls (n = 18) and cocaine polydrug users (n = 18) were matched on sex, age, alcohol consumption, and IQ (using the Raven's progressive matrices), and were tested by using the Global-Local task to measure the scope of attention. Cocaine polydrug users attended significantly more to local aspects of attended events, which fits with the idea that a reduced scope of attention may be associated with the perpetuation of the use of the drug.
Biochemical and Biophysical Research Communications, 2011
Ca2+ entry through the L-subtype (α1D, Cav1,3) of voltage-dependent calcium channels (VDCCs) seem... more Ca2+ entry through the L-subtype (α1D, Cav1,3) of voltage-dependent calcium channels (VDCCs) seems to selectively regulate the endocytotic response after the application of a single depolarizing pulse to voltage-clamped bovine chromaffin cells. Here we have found that L channel blockade with nifedipine transformed the exocytotic responses elicited by a double-pulse protocol, from depression to facilitation. This apparent paradoxical effect was
Pflugers Archiv-european Journal of Physiology, 2010
Sphingosine has been shown to modulate neurotransmitter release. Because membrane fusion and fiss... more Sphingosine has been shown to modulate neurotransmitter release. Because membrane fusion and fission involve lipid metabolism, we asked here whether sphingosine had a role in regulating endocytosis. To explore this hypothesis, we monitored changes of membrane capacitance (Cm) to study the effects of intracellular sphingosine on membrane retrieval after chromaffin cell stimulation with depolarising pulses (DPs). We found that: (1)
American journal of physiology. Cell physiology, 2014
At early life, the adrenal chromaffin cells respond with a catecholamine surge under hypoxic cond... more At early life, the adrenal chromaffin cells respond with a catecholamine surge under hypoxic conditions. This response depends on Ca(2+) entry through voltage-activated calcium channels (VACCs). We have investigated here three unresolved questions that concern this response in rat embryo chromaffin cells (ECCs): 1) the relative contribution of L (α1D, Cav1.3), N (α1B, Cav2.2), and PQ (α1A, Cav2.1) to the whole cell Ca(2+) current (ICa); 2) the relative contribution of L and N/PQ channels to the cytosolic Ca(2+) elevations triggered by hypoxia (Δ[Ca(2+)]c); and 3) the role of L and non-L high-VACCs in the regulation of the catecholamine surge occurring during prolonged (1 min) hypoxia exposure of ECCs. Nimodipine halved peak ICa and blocked 60% the total Ca(2+) entry during a 50-ms depolarizing pulse to 0 mV (QCa). Combined ω-agatoxin IVA plus ω-conotoxin GVIA (Aga/GVIA) blocked 30% of both ICa peak and QCa. This relative proportion of L- and non-L VACCs was corroborated by Western b...
A simplified technique to perform the duodeno-enteral anastomosis in the duodenal switch is prese... more A simplified technique to perform the duodeno-enteral anastomosis in the duodenal switch is presented. A linear stapled duodeno-jejunal side-to-side anastomosis is performed. The technique is easy and rapid to perform, avoids passing an anvil through the mouth of the patient and is safe for the patient, with satisfactory short-term results.
Medicina oral, patología oral y cirugía bucal, 2006
Study the loss or reduction of the cellular adhesion mediated for E-cadherin in oral leukoplakias... more Study the loss or reduction of the cellular adhesion mediated for E-cadherin in oral leukoplakias, oral squamous cell carcinomas and metastatic nodules. Study the loss of continuity of the laminin and collagen IV expression in the epithelial basal membrane from the biological development of the oral leukoplakias and oral carcinomas. we have studied 124 samples of patient pays leukoplakias and oral carcinomas with diverse diagnosis that embrace from normal epithelium (13 samples), mild dysplasias (2), moderate dysplasias (12), in situ carcinomas (13), microinvasive carcinomas (11) oral squamous cell carcinomas (64 samples) and metastatic nodules (9). 7 blocks of tissue microarrays were built with needle of 2mm and was carried out a study by means of immunohistochemical technique for E-cadherin (clone 36, Biogenex), Laminin (078P, Biogenex) and Collagen IV (PHM12, Biogenex). In Mild and Moderate Dysplasias the results present loss of E-cadherin, Laminin, and Collagen IV (20%) expressi...
Biochemical and Biophysical Research Communications, 2008
The view that Ca2+ entry through voltage-dependent Ca2+ channels (VDCC) and through nicotinic rec... more The view that Ca2+ entry through voltage-dependent Ca2+ channels (VDCC) and through nicotinic receptors for acetylcholine (nAChRs) causes equal catecholamine release responses in chromaffin cells, was reinvestigated here using new protocols. We have made two-step experiments consisting in an ACh prepulse followed by a depolarizing pulse (DP). In voltage-clamped bovine chromaffin cells an ACh prepulse caused a slow-rate release but
It is currently known that in CNS the extracellular matrix is involved in synaptic stabilization ... more It is currently known that in CNS the extracellular matrix is involved in synaptic stabilization and limitation of synaptic plasticity. However, it has been reported that the treatment with chondroitinase following injury allows the formation of new synapses and increased plasticity and functional recovery. So, we hypothesize that some components of extracellular matrix may modulate synaptic transmission. To test this hypothesis we evaluated the effects of chondroitin sulphate (CS) on excitatory synaptic transmission, cellular excitability, and neuronal plasticity using extracellular recordings in the CA1 area of rat hippocampal slices. CS caused a reversible depression of evoked field excitatory postsynaptic potentials in a concentration-dependent manner. CS also reduced the population spike amplitude evoked after orthodromic stimulation but not when the population spikes were antidromically evoked; in this last case a potentiation was observed. CS also enhanced paired-pulse facilitation and long-term potentiation. Our study provides evidence that CS, a major component of the brain perineuronal net and extracellular matrix, has a function beyond the structural one, namely, the modulation of synaptic transmission and neuronal plasticity in the hippocampus.
Why adrenal chromaffin cells express various subtypes of voltage-dependent Ca 2+ channels and whe... more Why adrenal chromaffin cells express various subtypes of voltage-dependent Ca 2+ channels and whether a given channel is specialized to perform a specific function are puzzling and unanswered questions. In this study, we have used the L Ca 2+ channel activator FPL64176 (FPL) to test the hypothesis that enhanced Ca 2+ entry through this channel favors the inhibition of N and PQ channels in voltage-clamped bovine adrenal chromaffin cells. Using 2 mM Ca 2+ as charge carrier and under the perforated-patch configuration (PPC) of the patch-clamp technique, FPL caused a paradoxical inhibition of the whole-cell inward Ca 2+ current (I Ca ). Such inhibition turned on into an augmentation upon cell loading with EGTA-AM. Also, under the whole-cell configuration (WCC) of the patchclamp technique, FPL decreased I Ca in the absence of EGTA from the pipette solution and increased the current in its presence. Using 2 mM Ba 2+ as charge carrier, FPL augmented the Ba 2+ current under both recording conditions, WCC and PPC. FPL augmented the residual current remaining after blockade of N and PQ channels with ω-conotoxin MVIIC or by holding the membrane potential at −50 mV. The data support the view that Ca 2+ entering the cell through the lesser inactivating L channels serves to modulate the more inactivating N and PQ channels. They also suggest a close colocalization of L and N/PQ Ca 2+ channels. This kind of L channel specialization may be relevant to cell excitability, exocytosis, and cell survival mechanisms.
During fast superfusion of bovine chromaffin cells with normal Krebs-HEPES solution containing 2 ... more During fast superfusion of bovine chromaffin cells with normal Krebs-HEPES solution containing 2 mM Ca 2+ , pulses of 100 µM ACh or 100 mM K + of increasing duration (1-5 s) caused similar exocytosis of about 3-4 µC catecholamine. Depletion of endoplasmic reticulum (ER) Ca 2+ by pretreatment with 1 µM thapsigargin, 10 mM caffeine and 10 µM ryanodine more than halved the responses to ACh but did not affect the responses to K + responses. In these ER Ca 2+ -depleted cells the protonophore carbonylcyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) (20 µM given during the 5 s preceding each pulse) augmented the responses to ACh responses fourfold for all pulse durations applied (1-5 s) whereas responses to K + were potentiated twofold with 1 to 2 s pulses but were not affected with longer pulse durations. ACh pulses applied to fura-2-loaded cells evoked increases of bulk cytosolic [Ca 2+ ] ([Ca 2+ ] c ) that were substantially smaller than those elicited by K + pulses. Confocal microscopy of fluo-3-loaded cells showed that ACh pulses elicited discrete and more localized [Ca 2+ ] c elevations, whereas K + pulses produced higher [Ca 2+ ] c transients that spread out quickly throughout the cytosol. These results suggest that mitochondria sense the increase of local [Ca 2+ ] c elicited by ACh (that evokes firing of action potentials) much better than that induced by K + (that produces sustained cell depolarisation). This implies that mitochondria are more sensitive to the local [Ca 2+ ] c changes resulting from the physiological triggering of action potentials by ACh.
The Fourier duality is an elegant technique to obtain sampling formulas in Paley-Wiener spaces. I... more The Fourier duality is an elegant technique to obtain sampling formulas in Paley-Wiener spaces. In this paper it is proved that there exists an analogous of the Fourier duality technique in the setting of shift-invariant spaces. In fact, any shiftinvariant space V ϕ with a stable generator ϕ is the range space of a bounded oneto-one linear operator T between L 2 (0, 1) and L 2 (R). Thus, regular and irregular sampling formulas in V ϕ are obtained by transforming, via T , expansions in L 2 (0, 1) with respect to some appropriate Riesz bases.
In this paper we investigate approximation from shift-invariant spaces by using generalized sampl... more In this paper we investigate approximation from shift-invariant spaces by using generalized sampling formulas. These sampling formulas involve samples of filtered versions of the function itself. The considered systems include averaging samplers, and classical sampling of the function and its derivatives. Under appropriate hypotheses on the generator ϕ of the shift-invariant space and on the involved systems, we derive stable generalized sampling formulas in a shift-invariant subspace of L p (R n ). From these generalized sampling formulas we construct approximation schemes valid for smooth functions. The approximation order depends both on the order for which the Strang-Fix conditions are satisfied by ϕ, and on the largest order of the derivatives appearing in the systems if any.
Objectives: Heightened body awareness can be adaptive and maladaptive. Improving body awareness h... more Objectives: Heightened body awareness can be adaptive and maladaptive. Improving body awareness has been suggested as an approach for treating patients with conditions such as chronic pain, obesity and post-traumatic stress disorder. We assessed the psychometric quality of selected self-report measures and examined their items for underlying definitions of the construct.
1 The eects of lubeluzole (a neuroprotective benzothiazole derivative) and its (7) enantiomer R91... more 1 The eects of lubeluzole (a neuroprotective benzothiazole derivative) and its (7) enantiomer R91154 on whole-cell currents through Ca 2+ channels, with 10 mM Ba 2+ as charge carrier (I Ba ), have been studied in bovine and mouse voltage-clamped adrenal chroman cells. Currents generated by applying 50 ms depolarizing test pulses to 0 mV, from a holding potential of 780 mV, at 10 s intervals had an average magnitude of 1 nA. 2 Lubeluzole and R91154 blocked the peak I Ba of bovine chroman cells in a time and concentrationdependent manner; their IC 50 s were 1.94 mM for lubeluzole and 2.54 mM for R91154. In a current-voltage protocol, lubeluzole (3 mM) inhibited peak I Ba at all test potentials. However, no obvious shifts of the I-V curve were detected. 3 After 10 min exposure to 3 mM lubeluzole, the late current (measured at the end of the pulse) was inhibited more than the peak current. Upon wash out of the drug, the inactivation reversed ®rst and then the peak current recovered. 4 Blockade of peak current was greater at more depolarizing holding potentials (i.e. 35% at 7110 mV and 87% at 750 mV, after 10 min superfusion with lubeluzole). Inactivation of the current was pronounced at 7110 mV, decreased at 780 mV and did not occur at 750 mV. 5 Intracellular dialysis of bovine voltage-clamped chroman cells with 3 mM lubeluzole caused neither blockade nor inactivation of I Ba . The external application of 3 mM lubeluzole to those dialysed cells produced inhibition as well as inactivation of I Ba . 6 The eects of lubeluzole (3 mM) on I Ba in mouse chroman cells were similar to those in bovine chroman cells. At 780 mV holding potential, a pronounced inactivation of the current led to greater blockade of the late I Ba (66%) as compared with peak I Ba (46% after 10 min superfusion with lubeluzole). 7 In mouse chroman cells approximately half of the whole-cell I Ba was sensitive to 3 mM nifedipine (L-type Ca 2+ channels) and the other half to 3 mM o-conotoxin MVIIC (non-L-type Ca 2+ channels). In o-conotoxin MVIIC-treated cells, 3 mM lubeluzole caused little blockade and inactivation of I Ba . However in nifedipine-treated cells, lubeluzole caused a pronounced blockade and inactivation of I Ba that reversed upon wash out of the compound. 8 The results are compatible with the idea that lubeluzole preferentially blocks non-L-types of voltagedependent Ca 2+ channels expressed by bovine and mouse chroman cells. The higher concentrations of the compound also block L-type Ca 2+ channels. The mechanism of inhibition involves the access of lubeluzole to the open channel from the outside of the cell and promotion of its inactivation. The dierential blockade of Ca 2+ channel subtypes might contribute to the neuroprotective actions of lubeluzole (which exhibit stereoselectivity). However, in view of the lack of stereoselectivity in blocking Ca 2+ channels, this eect cannot be the only explanation for the protective activity of lubeluzole in stroke.
Background: Of the putative psychopathological endophenotypes in major depressive disorder (MDD),... more Background: Of the putative psychopathological endophenotypes in major depressive disorder (MDD), the anhedonic subtype is particularly well supported. Anhedonia is generally assumed to reflect aberrant motivation and reward responsivity. However, research has been limited by a lack of objective measures of reward motivation. We present the Effort-Expenditure for Rewards Task (EEfRT or ''effort''), a novel behavioral paradigm as a means of exploring effort-based decision-making in humans. Using the EEfRT, we test the hypothesis that effort-based decision-making is related to trait anhedonia.
Chronic use of cocaine is associated with a reduced density of dopaminergic D2 receptors in the s... more Chronic use of cocaine is associated with a reduced density of dopaminergic D2 receptors in the striatum, with negative consequences for cognitive control processes. Increasing evidence suggests that cognitive control is also affected in recreational cocaine consumers. This study aimed at linking these observations to dopaminergic malfunction by studying the spontaneous eyeblink rate (EBR), a marker of striatal dopaminergic functioning, in adult recreational users and a cocaine-free sample that was matched on age, race, gender, and personality traits. Correlation analyses show that EBR is significantly reduced in recreational users compared to cocaine-free controls, suggesting that cocaine use induces hypoactivity in the subcortical dopamine system. Citation: Colzato LS, van den Wildenberg WPM, Hommel B (2008) Reduced Spontaneous Eye Blink Rates in Recreational Cocaine Users: Evidence for Dopaminergic Hypoactivity. PLoS ONE 3(10): e3461.
Despite the abundance of evidence that human perception is penetrated by beliefs and expectations... more Despite the abundance of evidence that human perception is penetrated by beliefs and expectations, scientific research so far has entirely neglected the possible impact of religious background on attention. Here we show that Dutch Calvinists and atheists, brought up in the same country and culture and controlled for race, intelligence, sex, and age, differ with respect to the way they attend to and process the global and local features of complex visual stimuli: Calvinists attend less to global aspects of perceived events, which fits with the idea that people's attentional processing style reflects possible biases rewarded by their religious belief system. Citation: Colzato LS, van den Wildenberg WPM, Hommel B (2008) Losing the Big Picture: How Religion May Control Visual Attention. PLoS ONE 3(11): e3679.
Cocaine is Europe's second preferred recreational... more Cocaine is Europe's second preferred recreational drug after cannabis but very little is known about possible cognitive impairments in the upcoming type of recreational cocaine user (monthly consumption). We asked whether recreational use of cocaine impacts early attentional selection processes. Cocaine-free polydrug controls (n = 18) and cocaine polydrug users (n = 18) were matched on sex, age, alcohol consumption, and IQ (using the Raven's progressive matrices), and were tested by using the Global-Local task to measure the scope of attention. Cocaine polydrug users attended significantly more to local aspects of attended events, which fits with the idea that a reduced scope of attention may be associated with the perpetuation of the use of the drug.
Biochemical and Biophysical Research Communications, 2011
Ca2+ entry through the L-subtype (α1D, Cav1,3) of voltage-dependent calcium channels (VDCCs) seem... more Ca2+ entry through the L-subtype (α1D, Cav1,3) of voltage-dependent calcium channels (VDCCs) seems to selectively regulate the endocytotic response after the application of a single depolarizing pulse to voltage-clamped bovine chromaffin cells. Here we have found that L channel blockade with nifedipine transformed the exocytotic responses elicited by a double-pulse protocol, from depression to facilitation. This apparent paradoxical effect was
Pflugers Archiv-european Journal of Physiology, 2010
Sphingosine has been shown to modulate neurotransmitter release. Because membrane fusion and fiss... more Sphingosine has been shown to modulate neurotransmitter release. Because membrane fusion and fission involve lipid metabolism, we asked here whether sphingosine had a role in regulating endocytosis. To explore this hypothesis, we monitored changes of membrane capacitance (Cm) to study the effects of intracellular sphingosine on membrane retrieval after chromaffin cell stimulation with depolarising pulses (DPs). We found that: (1)
American journal of physiology. Cell physiology, 2014
At early life, the adrenal chromaffin cells respond with a catecholamine surge under hypoxic cond... more At early life, the adrenal chromaffin cells respond with a catecholamine surge under hypoxic conditions. This response depends on Ca(2+) entry through voltage-activated calcium channels (VACCs). We have investigated here three unresolved questions that concern this response in rat embryo chromaffin cells (ECCs): 1) the relative contribution of L (α1D, Cav1.3), N (α1B, Cav2.2), and PQ (α1A, Cav2.1) to the whole cell Ca(2+) current (ICa); 2) the relative contribution of L and N/PQ channels to the cytosolic Ca(2+) elevations triggered by hypoxia (Δ[Ca(2+)]c); and 3) the role of L and non-L high-VACCs in the regulation of the catecholamine surge occurring during prolonged (1 min) hypoxia exposure of ECCs. Nimodipine halved peak ICa and blocked 60% the total Ca(2+) entry during a 50-ms depolarizing pulse to 0 mV (QCa). Combined ω-agatoxin IVA plus ω-conotoxin GVIA (Aga/GVIA) blocked 30% of both ICa peak and QCa. This relative proportion of L- and non-L VACCs was corroborated by Western b...
A simplified technique to perform the duodeno-enteral anastomosis in the duodenal switch is prese... more A simplified technique to perform the duodeno-enteral anastomosis in the duodenal switch is presented. A linear stapled duodeno-jejunal side-to-side anastomosis is performed. The technique is easy and rapid to perform, avoids passing an anvil through the mouth of the patient and is safe for the patient, with satisfactory short-term results.
Medicina oral, patología oral y cirugía bucal, 2006
Study the loss or reduction of the cellular adhesion mediated for E-cadherin in oral leukoplakias... more Study the loss or reduction of the cellular adhesion mediated for E-cadherin in oral leukoplakias, oral squamous cell carcinomas and metastatic nodules. Study the loss of continuity of the laminin and collagen IV expression in the epithelial basal membrane from the biological development of the oral leukoplakias and oral carcinomas. we have studied 124 samples of patient pays leukoplakias and oral carcinomas with diverse diagnosis that embrace from normal epithelium (13 samples), mild dysplasias (2), moderate dysplasias (12), in situ carcinomas (13), microinvasive carcinomas (11) oral squamous cell carcinomas (64 samples) and metastatic nodules (9). 7 blocks of tissue microarrays were built with needle of 2mm and was carried out a study by means of immunohistochemical technique for E-cadherin (clone 36, Biogenex), Laminin (078P, Biogenex) and Collagen IV (PHM12, Biogenex). In Mild and Moderate Dysplasias the results present loss of E-cadherin, Laminin, and Collagen IV (20%) expressi...
Biochemical and Biophysical Research Communications, 2008
The view that Ca2+ entry through voltage-dependent Ca2+ channels (VDCC) and through nicotinic rec... more The view that Ca2+ entry through voltage-dependent Ca2+ channels (VDCC) and through nicotinic receptors for acetylcholine (nAChRs) causes equal catecholamine release responses in chromaffin cells, was reinvestigated here using new protocols. We have made two-step experiments consisting in an ACh prepulse followed by a depolarizing pulse (DP). In voltage-clamped bovine chromaffin cells an ACh prepulse caused a slow-rate release but
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Papers by Antonio García