Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Bed nucleus of the stria terminalis alpha(1)-adrenoceptor modulates baroreflex cardiac component in unanesthetized rats

Full text
Author(s):
Crestani, Carlos C. [1] ; Alves, Fernando H. F. [1] ; Resstel, Leonardo B. M. [1] ; Correa, Fernando M. A. [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Pharmacol, BR-14090090 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Brain Research; v. 1245, p. 108-115, DEC 15 2008.
Web of Science Citations: 25
Abstract

The bed nucleus of stria terminalis (BST) has a tonic modulating role on the baroreflex parasympathetic component. In the present study, we verified that local BST-adrenoceptors modulate baroreflex-evoked bradycardiac responses in unanesthetized rats. Bilateral microinjection of the selective alpha(1)-adrenoceptor antagonist WB4101 (15 nmol/100 nL) into the BST increased the gain of reflex bradycardia in response to mean arterial pressure increases caused by intravenous (i.v.) infusion of phenylephrine, suggesting that BST alpha(1)-adrenoceptors modulate baroreflex bradycardiac response. Bilateral microinjection of either the selective alpha(2)-adrenoceptor antagonist RX821002 (15 nmol/100 nL) or the non-selective beta-adrenoceptor antagonist propranolol (15 nmol/100 nL) into the BST had not affected baroreflex bradycardia. Animals were pretreated intravenously with the cholinergic muscarinic receptor antagonist homatropine methyl bromide (HMB, 1.5 mg/Kg) to test the hypothesis that activation of alpha(1)-adrenoceptors in the BST would modulate the baroreflex parasympathetic component. Baroreflex bradycardiac responses evoked before and after BST treatment with WB4101 were no longer different when rats were pretreated with HMB. These results suggest that parasympathetic activation accounts for the effects saw after BST pharmacological manipulation and ruling out the possibility of a sympathetic withdraw. In conclusion, our data point out that local alpha(1)-adrenoceptors mediate the BST tonic influence on the baroreflex bradycardiac response modulating parasympathetic cardiac activity. (C) 2008 Elsevier B.V. All rights reserved. (AU)