Aging-induced decrease of cholinergic response and calcium sensitivity on rat jejunum contractions

Aging-induced decrease of cholinergic response and calcium sensitivity on rat jejunum contractions

Author Lopes, Guiomar Silva Autor UNIFESP Google Scholar
Smaili, Soraya Soubhi Autor UNIFESP Google Scholar
Caricati-Neto, Afonso Autor UNIFESP Google Scholar
Vladimirova, Irina Google Scholar
Jurkiewicz, Aron Autor UNIFESP Google Scholar
Jurkiewicz, Neide Hyppolito Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Johns Hopkins Univ
Abstract The role of aging on contraction or relaxation through muscarinic or alpha-adrenergic receptors, respectively, was studied in isolated rat jejunum. Furthermore, the influence of extracellular calcium was analyzed, through functional and radioligand binding assays. The rank order of potency for selective muscarinic antagonists for M-1, M-2, and M-3 receptor subtypes, measured from affinity (pA(2)) values, was p-fluorohexahydrosiladifenidol (pFHHSiD) (M-3) > pirenzepine (M-1) > methoctramine (M-2), indicating a predominance Of M-3 subtype. This order was unchanged with age. Contractions by muscarinic agonist methacholine (MCh) were diminished in aged rats, resulting in lower apparent affinity (pD(2)) values, compared with adult controls. A larger decrease of MCh contractions occurred in aged rats after Ca2+ withdrawal or after the calcium channel blocker isradipine. Changes were not detected for relaxation by adrenergic agonists. In conclusion, aging caused a decrease of MCh potency, which is probably related to the reduction of calcium sensitivity in jejunum.
Language English
Date 2007-03-01
Published in Journals Of Gerontology Series A-biological Sciences And Medical Sciences. Washington: Gerontological Soc Amer, v. 62, n. 3, p. 264-270, 2007.
ISSN 1079-5006 (Sherpa/Romeo, impact factor)
Publisher Gerontological Soc Amer
Extent 648-653
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000250763300005

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