Central inhibition of nitric oxide synthase modulates upper
gastrointestinal motor activity.
Ohta, Daisaku, Ching-Wen Lee, Sushil K. Sarna, Robert E. Condon, and
Ivan M. Lang.
Departments of Surgery, Physiology and Medicine, Medical College of
Wisconsin and Zablocki VA Medical Center, Milwaukee, WI 53226
APStracts 3:0174G, 1996.
We investigated the role of central NO synthase inhibition in the
modulation of fasting gastrointestinal motor activity and gastric
emptying rate of solid nutrient meals in conscious dogs. N -L-nitro
-arginine methyl ester (L-NAME) and N -nitro-L-arginine (L-NNA) were
infused intracerebroventricularly. Circular muscle contractions were
recorded with surgically implanted strain gauge transducers. Gastric
emptying was measured by a radio-labeled meal. The inhibition of NO
synthase in the brain suppressed phase III activity in the stomach
and the duodenum but not in the jejunum or the ileum. However, the
central inhibition of NO synthase had no significant effect on the
rate of gastric emptying of solid nutrient meals or the duration of
postprandial disruption of MMC cycling. The central actions of NO
synthase inhibition were blocked by bilateral truncal vagotomy but
not by intravenous administration of propranolol or phentolamine. We
conclude that the inhibition of NO synthase inhibition in the brain
generates a stimulus that selectively inhibits gastric and duodenal
phase III activities. This stimulus, however, may not affect the
postprandial gastroduodenal motor activity or the rate of gastric
emptying of solid nutrient meals.
Received 21 February 1996; accepted in final form 27 August 1996.
APS Manuscript Number G65-6.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996