AJP - Gastrointestinal and Liver Physiology, Vol 259, Issue 2 321-G326, Copyright © 1990 by American Physiological Society

ARTICLES

Gastric effects of TRH analogue and bicuculline injected into dorsal motor vagal nucleus in cats

H. S. Feng, R. B. Lynn, J. Han and F. P. Brooks
School of Medicine, University of Pennsylvania, Philadelphia 19104.

We investigated the gastric acid secretory and motility responses to microinjection into the dorsal motor nucleus of the vagus (DMV) of RX 77368, a stable thyrotropin-releasing hormone (TRH) analogue, and bicuculline, a gamma-aminobutyric acid (GABAA) receptor antagonist in ketamine-chloralose-anesthetized cats. Gastric acid output was collected every 15 min through a gastric cannula after saline flush and titrated to pH 7.0. Antral contractions were continuously recorded by an extraluminal strain gauge force transducer. The chemicals were dissolved in saline and unilaterally microinjected in volumes of 200 nl. RX 77368 or bicuculline microinjected into the DMV induced significant dose-dependent (50-500 ng) increases in gastric acid secretion and significant dose-dependent (50-200 ng) increases in the force of antral contractions. In response to both chemicals the gastric acid output increased in the first 15 min and peaked in the second and third collections. RX 77368 (500 ng) had a second greater peak 90 min after microinjection. The motility responses were rapid in onset and lasted 60 min for RX 77368 and 30 min for bicuculline. The minimal effective dose for eliciting increased motility was consistently lower than inducing acid secretion. Electrical stimulation of the DMV with 100 microA, 50-Hz, and 0.2-ms pulse duration increased the force of antral contractions but had no effect on gastric acid secretion. Our results demonstrate that the DMV exerts important control over both gastric acid secretion and motility in cats. TRH exerts a stimulatory influence, while GABAA receptors mediate an inhibitory influence on this vagal control.

This article has been cited by other articles:

				S.-Y. Zhou, Y.-X. Lu, H. Yao, and C. Owyang Spatial organization of neurons in the dorsal motor nucleus of the vagus synapsing with intragastric cholinergic and nitric oxide/VIP neurons in the rat Am J Physiol Gastrointest Liver Physiol, May 1, 2008; 294(5): G1201 - G1209. [Abstract] [Full Text] [PDF]

				Z. Tan, R. Fogel, C. Jiang, and X. Zhang Galanin Inhibits Gut-Related Vagal Neurons in Rats J Neurophysiol, May 1, 2004; 91(5): 2330 - 2343. [Abstract] [Full Text] [PDF]

				C. Sevoz-Couche, M.-A. Comet, M. Hamon, and R. Laguzzi Role of Nucleus Tractus Solitarius 5-HT3 Receptors in the Defense Reaction-Induced Inhibition of the Aortic Baroreflex in Rats J Neurophysiol, October 1, 2003; 90(4): 2521 - 2530. [Abstract] [Full Text] [PDF]

				M. Kobashi, M. Mizutani, and R. Matsuo Water stimulation of the posterior oral cavity induces inhibition of gastric motility Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2000; 279(3): R778 - R785. [Abstract] [Full Text] [PDF]

				C.-S. Yuan, D. Liu, and A. S. Attele GABAergic Effects on Nucleus Tractus Solitarius Neurons Receiving Gastric Vagal Inputs J. Pharmacol. Exp. Ther., August 1, 1998; 286(2): 736 - 741. [Abstract] [Full Text]