Thais Ribeiro - Academia.edu (original) (raw)

Papers by Thais Ribeiro

Psychology and Neuroscience, 2012

This experiment evaluated the effects of superimposing the Estes-Skinner Conditioned Emotional Re... more This experiment evaluated the effects of superimposing the Estes-Skinner Conditioned Emotional Response (CER) procedure on one of two components of a multiple schedule. The question was whether CER conditioning occurred under contextual control. The procedure had four experimental phases: (1) baseline of operant responding under a two-component multiple schedule (mult VI 30 VI 30), one component correlated with the house light on and the other correlated with the house light off (light/ dark components), (2) introduction of tone-shock pairings during the light component only, (3) return to baseline contingencies, and (4) reintroduction of the tone (but not shock) in the light component. Three Wistar rats showed robust suppression of responding in the light component, and the suppression also partially generalized to the dark component. The suppression was stronger during the pre-aversive stimulus than during the intervals immediately before and after its presentation. Responding partially recovered under baseline contingencies, but response rates remained lower in the light component than in the dark component. Thus, under the present experimental conditions, the context in which CER conditioning occurred (i.e., the house light-illuminated chamber) also produced conditioned suppression, and contextual control of suppressed responding generalized to another context, one that shared some but not all elements of the first context (i.e., the same chamber not illuminated by a house light). These results have direct implications for our understanding of emotional conditioning produced in the laboratory and for analysis of related phenomena addressed in the clinic.

Brain Research, 2010

Peripheral chemoreflex activation has been considered the key drive for the overactivity of the s... more Peripheral chemoreflex activation has been considered the key drive for the overactivity of the sympathetic nervous system observed in some pathological conditions such as sleep obstructive apnea. In addition, increases in angiotensin-II-derived reactive oxygen species found in some autonomic regulatory brain areas have been implicated in hypertension.

European Journal of Pharmacology, 2012

The reduced availability of nitric oxide (NO) is associated with cardiovascular diseases. Therefo... more The reduced availability of nitric oxide (NO) is associated with cardiovascular diseases. Therefore, NO donors such as organic nitrates are useful for the treatment of these disorders. The 2-nitrate-1,3dibuthoxypropan (NDBP) is an organic nitrate synthesized from glycerin, which the pharmacological effects have not been investigated. In this study we evaluated the vasorelaxant effect induced by NDBP in superior mesenteric artery from rats. In phenylephrine pre-contracted artery rings, NDBP (10 À 8 -10 À 4 M) elicited concentration-dependent and endothelium-independent relaxation, which were attenuated by hydroxocobalamin-HDX (30 mM), a NO extracellular scavenger, and 1-H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one-ODQ (10 mM), an inhibitor of soluble guanylyl cyclase (sGC). In addition, the NDBP-induced relaxation was reduced by non-selective K þ channels blocker KCl (20 mM) or selective K þ channels blockers such as tetraethylammonium-TEA (B KCa , 1 mM), charybdotoxin-ChTX (B KCa , 100 nM), glibenclamide (K ATP , 1 mM) and 4-aminopyridine-4-AP (K V , 1 mM). In preparations with ODQ (10 mM) plus TEA (1 mM), the response was virtually abolished. In rat smooth muscle cells culture, NDBP (10 À 6 -10 À 4 M) caused concentration-dependent increases in NO levels. These findings suggest that NDBP causes vasorelaxation through NO generation and activation of the sCG/cGMP/PKG pathway.

Psychology and Neuroscience, 2012

This experiment evaluated the effects of superimposing the Estes-Skinner Conditioned Emotional Re... more This experiment evaluated the effects of superimposing the Estes-Skinner Conditioned Emotional Response (CER) procedure on one of two components of a multiple schedule. The question was whether CER conditioning occurred under contextual control. The procedure had four experimental phases: (1) baseline of operant responding under a two-component multiple schedule (mult VI 30 VI 30), one component correlated with the house light on and the other correlated with the house light off (light/ dark components), (2) introduction of tone-shock pairings during the light component only, (3) return to baseline contingencies, and (4) reintroduction of the tone (but not shock) in the light component. Three Wistar rats showed robust suppression of responding in the light component, and the suppression also partially generalized to the dark component. The suppression was stronger during the pre-aversive stimulus than during the intervals immediately before and after its presentation. Responding partially recovered under baseline contingencies, but response rates remained lower in the light component than in the dark component. Thus, under the present experimental conditions, the context in which CER conditioning occurred (i.e., the house light-illuminated chamber) also produced conditioned suppression, and contextual control of suppressed responding generalized to another context, one that shared some but not all elements of the first context (i.e., the same chamber not illuminated by a house light). These results have direct implications for our understanding of emotional conditioning produced in the laboratory and for analysis of related phenomena addressed in the clinic.

Brain Research, 2010

Peripheral chemoreflex activation has been considered the key drive for the overactivity of the s... more Peripheral chemoreflex activation has been considered the key drive for the overactivity of the sympathetic nervous system observed in some pathological conditions such as sleep obstructive apnea. In addition, increases in angiotensin-II-derived reactive oxygen species found in some autonomic regulatory brain areas have been implicated in hypertension.

European Journal of Pharmacology, 2012

The reduced availability of nitric oxide (NO) is associated with cardiovascular diseases. Therefo... more The reduced availability of nitric oxide (NO) is associated with cardiovascular diseases. Therefore, NO donors such as organic nitrates are useful for the treatment of these disorders. The 2-nitrate-1,3dibuthoxypropan (NDBP) is an organic nitrate synthesized from glycerin, which the pharmacological effects have not been investigated. In this study we evaluated the vasorelaxant effect induced by NDBP in superior mesenteric artery from rats. In phenylephrine pre-contracted artery rings, NDBP (10 À 8 -10 À 4 M) elicited concentration-dependent and endothelium-independent relaxation, which were attenuated by hydroxocobalamin-HDX (30 mM), a NO extracellular scavenger, and 1-H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one-ODQ (10 mM), an inhibitor of soluble guanylyl cyclase (sGC). In addition, the NDBP-induced relaxation was reduced by non-selective K þ channels blocker KCl (20 mM) or selective K þ channels blockers such as tetraethylammonium-TEA (B KCa , 1 mM), charybdotoxin-ChTX (B KCa , 100 nM), glibenclamide (K ATP , 1 mM) and 4-aminopyridine-4-AP (K V , 1 mM). In preparations with ODQ (10 mM) plus TEA (1 mM), the response was virtually abolished. In rat smooth muscle cells culture, NDBP (10 À 6 -10 À 4 M) caused concentration-dependent increases in NO levels. These findings suggest that NDBP causes vasorelaxation through NO generation and activation of the sCG/cGMP/PKG pathway.