title: Prelimbic cortex GABAAreceptors are involved in the mediation of restraint stress-evoked cardiovascular responses.
abstract: Stress is a response of the organism to homeostasis-threatening stimuli and is coordinated by two main neural systems: the hypothalamic-pituitary-adrenal and the autonomic nervous system. Acute restraint stress (RS) is a model of unavoidable stress, which is characterized by autonomic responses including an increase in mean arterial pressure (MAP) and heart rate (HR), as well as a drop in tail temperature. The prelimbic cortex (PL) has been implicated in the modulation of functional responses caused by RS. The present study aimed to evaluate the role of PL GABAergic neurotransmission in the modulation of autonomic changes induced by RS. Bilateral microinjection of the GABAAreceptor antagonist bicuculline methiodide into the PL reduced pressor and tachycardic responses evoked by RS, in a dose-dependent manner, without affecting the tail temperature drop evoked by RS. In order to investigate which peripheral autonomic effector modulated the reduction in RS-cardiovascular responses caused by the blockade of PL GABAAreceptors, rats were intravenously pretreated with either atenolol or homatropine methylbromide. The blockade of the cardiac sympathetic nervous system with atenolol blunted the reducing effect of PL treatment with bicuculline methiodide on RS-evoked pressor and tachycardic responses. The blockade of the parasympathetic nervous system with homatropine methylbromide, regardless of affecting the beginning of the tachycardic response, did not impact on the reduction of RS-evoked tachycardic and pressor responses caused by the PL treatment with bicuculline methiodide. The present results indicate that both cardiac sympathetic and parasympathetic activities are involved in the reduction of RS-evoked cardiovascular responses evidenced after the blockade of PL GABAAreceptors by bicuculline methiodide.
authors: a Department of Pharmacology of the School of Medicine of Ribeirão Preto , University of São Paulo , Ribeirão Preto , São Paulo , Brazil.
authors: Aline
authors: A
authors: Fassini
authors: a Department of Pharmacology of the School of Medicine of Ribeirão Preto , University of São Paulo , Ribeirão Preto , São Paulo , Brazil.
authors: Leonardo B M
authors: LB
authors: Resstel
authors: a Department of Pharmacology of the School of Medicine of Ribeirão Preto , University of São Paulo , Ribeirão Preto , São Paulo , Brazil.
authors: Fernando M A
authors: FM
authors: Corrêa
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001640:Bicuculline / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D018756:GABA Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D008032:Limbic System / Q000503:physiopathology*; D008297:Male; D008845:Microinjections; D010276:Parasympatholytics / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism*; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000503:physiopathology*; D009435:Synaptic Transmission; D013610:Tachycardia / Q000139:chemically induced / Q000503:physiopathology; D014326:Tropanes / Q000494:pharmacology
chemical_list: D000319:Adrenergic beta-Antagonists; D018756:GABA Antagonists; D010276:Parasympatholytics; D011963:Receptors, GABA-A; D014326:Tropanes; C017069:bicuculline methiodide; D001262:Atenolol; C100236:homatropine; D001640:Bicuculline
keywords: GABAA receptors; Medial prefrontal cortex; acute stress; autonomic nervous system; cardiovascular; restraint