AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 5 660-G664, Copyright © 1986 by American Physiological Society
Vagal nerve stimulation causes noncholinergic dilatation of gastric arterioles
T. Morishita and P. H. Guth
Vagal nerve stimulation causes prompt dilatation of gastric submucosal
arterioles (the vessels that control gastric mucosal blood flow) in rats.
In vivo microscopy was used to determine whether this direct vasodilator
effect of vagal nerve stimulation on rat gastric submucosal arterioles is
mediated by cholinergic fibers. Acetylcholine and atropine were topically
applied to the submucosa. The distal end of the severed vagus nerve was
electrically stimulated (8 V, 2 ms, 6 Hz, 20 s) subdiaphragmatically.
Diameter changes of the submucosal arterioles were videotaped and measured
with an image-splitting technique on playback of the videotapes.
Acetylcholine, 10(-7) to 10(-5) M, dilated the arterioles dose dependently.
Atropine prevented the acetylcholine-induced dilatation, 10(-5) M, nearly
completely inhibiting the dilatation. Vagal nerve stimulation dilated the
arterioles promptly, and this dilatation was not blocked by 10(-5) M
atropine, a dose that blocked the acetylcholine-induced dilatation. These
results indicate that vagal nerve stimulation causes atropine-resistant,
noncholinergic dilatation of gastric submucosal arterioles in rats.
