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Type: Artigo de periódico
Title: Effects Of Escapable And Inescapable Foot-shock On Rat Atrial Beta-adrenoceptors.
Author: Bassani, R A
Bassani, J W
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 beta 1-adrenoceptor antagonist) was detected. However, a decrease of the maximum response to soterenol, a partial agonist at beta 1-adrenoceptors, occurred only after inescapable foot-shock. The enhanced sensitivity to ISO was abolished by butoxamine (a selective beta 2-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 beta 1-adrenoceptors but not the increased participation of beta 2-adrenoceptors in the response of the rat sinoatrial node to catecholamines after repeated foot-shock.
Subject: Animals
Heart Atria
Heart Rate
Rats, Wistar
Receptors, Adrenergic, Beta
Stress, Psychological
Sympathectomy, Chemical
Citation: Pharmacology, Biochemistry, And Behavior. v. 44, n. 4, p. 869-75, 1993-Apr.
Rights: fechado
Identifier DOI: 
Date Issue: 1993
Appears in Collections:Unicamp - Artigos e Outros Documentos

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