Gastric distension-induced c-fos expression in catecholaminergic
neurons of rat dorsal vagal complex.
Willing, Alison E., and Hans-Rudolf Berthoud.
Neuroscience Laboratory, Pennington Biomedical Research Center,
Louisiana State University, Baton Rouge, Louisiana, 70808
APStracts 3:0288R, 1996.
Functionally specific vagal afferents were stimulated by gastric
balloon distension in non-anesthetized rats, followed by double c
-fos/dopamine-b-hydroxylase (DBH) immunocyto-chemistry, to identify
second order neurons in the dorsal vagal complex. Continuous and
repeated, phasic distension with similar volumes produced similar
numbers and patterns of c-fos expression, with most of the activated
neurons in the medial and commissural nts and dorsal motor nucleus
(dmnX). Larger distension activated significantly more neurons in all
responsive areas, but there was no differential effect. In most nts
subnuclei and the dmnX, a small (3%-5%) proportion of gastric
distension-activated neurons was DBH-immunoreactive, and this
proportion did not significantly change with type of distension. With
continuous and repeated, small distensions, 10%-12%, and with the
large distension, 22%-30%, of all DBH-IR neurons expressed c-fos. The
results suggest a large degree of convergence between rapidly
adapting mucosal receptors and slowly adapting tension receptors, but
not between low and high-threshold tension receptors, and a
relatively minor role of catecholaminergic second order neurons in
the dissemination of distension signals in the brain.
Received 26 April 1996; accepted in final form 2 July 1996.
APS Manuscript Number R235-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 August 1996