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Type: Artigo de periódico
Title: Chronotropic Response Of Beta-adrenergic-, Muscarinic-, And Calcitonin Gene-related Peptide-receptor Agonists In Right Atria From Neonatal Capsaicin-treated Rats.
Author: Gasparetti, Alessandra L
Hyslop, Stephen
Costa, Soraia K P
Priviero, Fernanda B M
De Nucci, Gilberto
Antunes, Edson
Zanesco, Angelina
Abstract: We evaluated the potency of isoproterenol, carbachol, pilocarpine and calcitonin gene-related peptide (CGRP) in the rat right atria at 30, 60 and 90 days after neonatal capsaicin treatment. Neonatal rats were pretreated on the second day of life with capsaicin (50 mg/kg). The capsaicin pretreatment caused a five-fold rightward shift at the pEC(50) level on the concentration-response curves to isoproterenol in 30-day-old rats. Propranolol (10 mg/kg, given 15 min prior to capsaicin treatment) prevented this subsensitivity. No changes in the potency of isoproterenol were observed at 60 and 90 days after capsaicin pretreatment. The potency and maximal responses of CGRP in the right atria in 30-day-old rats were significantly higher than in 60- and 90-day-old rats; however, no differences were found between control and capsaicin groups. The potency and maximal responses to carbachol and pilocarpine were not changed in all groups. The neonatal capsaicin treatment reduced by about 74% the CGRP content in the heart in all groups. In summary, capsaicin treatment in newborn rats produces a desensitization of chronotropic response mediated by beta-adrenoceptors in isolated right atria from 30-day-old rats possibly due to a massive release of catecholamines.
Subject: Adrenergic Beta-agonists
Animals, Newborn
Calcitonin Gene-related Peptide
Cholinergic Agonists
Dose-response Relationship, Drug
Heart Atria
Muscarinic Agonists
Rats, Wistar
Receptors, Adrenergic, Beta
Receptors, Calcitonin Gene-related Peptide
Receptors, Muscarinic
Time Factors
Citation: Neuroscience Letters. v. 325, n. 3, p. 147-50, 2002-Jun.
Rights: fechado
Date Issue: 2002
Appears in Collections:Unicamp - Artigos e Outros Documentos

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