Neural circuitry of capsaicin-sensitive afferents innervating
submucosal arterioles in the guinea pig ileum.
Vanner, S., and M. Bolton.
Depts. of Medicine and Physiology, Queen's University, Kingston,
Ontario, Canada
APStracts 2:0260G, 1995.
The circuitry of capsaicin-sensitive nerves innervating submucosal
arterioles in the guinea pig ileum was examined. The orientation of
in vitro submucosal preparations in a double chamber bath was varied
so that nerves on differing segments of arterioles could be
stimulated with capsaicin. Capsaicin-evoked dilation of
preconstricted arterioles was recorded using video-microscopy.
Superfusion of capsaicin onto either proximal or distal segments of a
parent arteriole divided between the chambers evoked a dilation in
the opposite chamber (63%and 58%, respectively) but had no effect on
extrinsically denervated preparations. When the divider separated the
vascular arcades joining two parent arterioles on the opposite or
same side of the intestine, capsaicin evoked little or no response
(8% and 11%,respectively). Capsaicin stimulation confined to one
branch of a single vessel dilated the opposite branch (42%). In
preparations with adjacently attached mucosa, application of
capsaicin to the mucosa dilated arterioles in the opposite chamber.
These findings suggest that capsaicin stimulation of the mucosa
evokes dilation of arterioles through a submucosal reflex and that
both afferent and efferent elements are confined to the submucosa and
mucosa.
Received 6 April 1995; accepted in final form 6 December 1995.
APS Manuscript Number G141-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95