Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/64157
Type: Artigo de periódico
Title: EFFECTS OF ESCAPABLE AND INESCAPABLE FOOT-SHOCK ON RAT ATRIAL BETA-ADRENOCEPTORS
Author: BASSANI, RA
BASSANI, JWM
Abstract: The chronotropic responsiveness to norepinephrine (NE) and isoproterenol (ISO) was determined in right atria isolated from rats submitted to repeated escapable or inescapable foot-shock. Significant postjunctional supersensitivity to ISO, but not to NE, was observed in both groups. No significant change in the pA2 value of metoprolol (a selective beta1-adrenoceptor antagonist) was detected. However, a decrease of the maximum response to soterenol, a partial agonist at beta1-adrenoceptors, occurred only after inescapable foot-shock. The enhanced sensitivity to ISO was abolished by butoxamine (a selective beta2-adrenoceptor antagonist) and accompanied by a marked increase in the pA2 Value of this antagonist. We conclude that the ability to control the shock prevented the down-regulation of the pacemaker beta1-adrenoceptors but not the increased participation of beta2-adrenoceptors in the response of the rat sinoatrial node to catecholamines after repeated foot-shock.
Subject: ESCAPABLE AND INESCAPABLE FOOT-SHOCK
STRESS
BETA-ADRENOCEPTORS
CATECHOLAMINES
CARDIAC PACEMAKER
Country: Inglaterra
Editor: Pergamon-elsevier Science Ltd
Rights: aberto
Identifier DOI: 10.1016/0091-3057(93)90019-P
Date Issue: 1993
Appears in Collections:Unicamp - Artigos e Outros Documentos

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