Journals of Gerontology Series A: Biological Sciences and Medical Sciences Large Type Edition
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lopes, G. S.
Right arrow Articles by Jurkiewicz, N. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lopes, G. S.
Right arrow Articles by Jurkiewicz, N. H.
The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 62:264-270 (2007)
© 2007 The Gerontological Society of America

Aging-Induced Decrease of Cholinergic Response and Calcium Sensitivity on Rat Jejunum Contractions

Guiomar Silva Lopes, Soraya Soubhi Smaili, Afonso Caricati Neto, Irina Vladimirova, Aron Jurkiewicz and Neide Hyppolito Jurkiewicz

1 Department of Pharmacology, Federal University of São Paulo (UNIFESP), Brazil.
2 Bogomoletz Institute of Physiology, Kiev, Ukraine.

Address correspondence to Guiomar Silva Lopes, MD, PhD, Rua Três de Maio, 100 São Paulo, 04044-020-Brazil. E-mail: guiolopes{at}terra.com.br

The role of aging on contraction or relaxation through muscarinic or Formula-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 M1, M2, and M3 receptor subtypes, measured from affinity (pA2) values, was p-fluorohexahydrosiladifenidol (pFHHSiD) (M3) > pirenzepine (M1) > methoctramine (M2), indicating a predominance of M3 subtype. This order was unchanged with age. Contractions by muscarinic agonist methacholine (MCh) were diminished in aged rats, resulting in lower apparent affinity (pD2) 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.







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
All GSA journals The Gerontologist
Journals of Gerontology Series B: Psychological Sciences and Social Sciences
Copyright © 2007 by The Gerontological Society of America.