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Effects of aging on cholinergic neuromuscular transmission in isolated small intestine of ad libitum fed and calorically-restricted rats

Hoyle, C. H. V. and Saffrey, M. J. (2012). Effects of aging on cholinergic neuromuscular transmission in isolated small intestine of ad libitum fed and calorically-restricted rats. Neurogastroenterology & Motility, 24(6) pp. 586–592.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1111/j.1365-2982.2012.01913.x
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Abstract

Background. Age-associated losses of enteric neurons have been described. In rat ileum, myenteric neurons lost during aging have been reported to be predominantly cholinergic, and caloric restriction (CR) has been shown protect against these losses. Cholinergic myenteric neurons include excitatory motoneurons, so the aim of this work was to determine whether neuronal loss in ad libitum (AL)-fed animals is reflected in dysfunctional cholinergic neuromuscular transmission, and if CR reduces any such dysfunction.

Methods. Effects of electrical field stimulation (EFS) and applied acetylcholine (ACh) were examined in the longitudinal muscle of isolated ileal segments from 6-month-old rats and from 13- and 24-month-old rats fed either AL or CR diets.

Key Results. Contractile responses to EFS were abolished by atropine and potentiated by the acetylcholinesterase inhibitor, eserine. Frequency-response relationships were not significantly different amongst the three age-groups. Sensitivity to applied ACh, however, was three-fold lower in the oldest animals (p < 0.05). Eserine potentiated responses to ACh; there were no statistically significant differences amongst the sensitivities to ACh in its presence. No significant differences between AL and CR fed animals were measured, although variability was less in CR fed than in AL fed groups.

Conclusions & Inferences. The cholinergic system supplying the rat ileum longitudinal muscle did not appear to be impaired in old age. Decreased sensitivity to applied ACh in old tissues may have been due to increased acetylcholinesterase activity. Caloric restriction had no significant effect on responses to EFS or applied Ach. The implications of these results are discussed.

Item Type: Journal Article
Copyright Holders: 2012 Blackwell Publishing Ltd
ISSN: 1365-2982
Project Funding Details:
Funded Project NameProject IDFunding Body
SAGE Initiative108/SAG10013BBSRC
Keywords: aging; acetylcholine; acetylcholinesterase; small intestine; smooth muscle; caloric restriction
Academic Unit/Department: Science > Life, Health and Chemical Sciences
Interdisciplinary Research Centre: Biomedical Research Network (BRN)
Related URLs:
Item ID: 32955
Depositing User: Jill Saffrey
Date Deposited: 05 Mar 2012 14:48
Last Modified: 21 Mar 2014 10:18
URI: http://oro.open.ac.uk/id/eprint/32955
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