The inhibitory effect of electrical acupuncture on gastric acid
secretion is mediated via [beta]-endorphin and somatostatin in
dogs.
Jin, H. O., L Zhou, K. Y. Lee, T. M. Chang, W. Y. Chey.
University of Rochester School of Medicine and Dentistry,
Department of Medicine, Division of Gastroenterology and Hepatology,
Center for Digestive and Liver Diseases, Rochester, New York
APStracts 3:0061G, 1996.
Electroacupuncture (EAP) was shown to inhibit basal gastric acid
secretion in dogs and Sham feeding-stimulated acid secretion in
humans. However, its effect on a meal-stimulated acid secretion in
dogs and its mechanisms involved remain unclear. In 5 dogs prepared
with gastric cannulas, gastric acid secretion was determined by a dye
dilution technique for 60 min after intragastric administration of
200 ml of 4% mixed amino acid meal in six different experiments
(Expt); Expt. 1: no acupuncture, Expt. 2: sham electroacupuncture
(SAP), Expt. 3: EAP, Expt. 4: EAP plus naloxone, Expt. 5: naloxone
alone, Expt. 6: intravenous infusion of somatostatin (SS) and
vasoactive intestinal peptide (VIP) at the doses of 0.5 and 1.0
[mu]g.kg-1.h-1, respectively. EAP was performed on 3 different points
including Pishu, ZusanLi, and Neiguan. Biphasic electrical pulse, 25
-100 Hz, 12-16 mA, was applied continuously via needles for 75 min,
starting 15 min before meal. SAP on non-acupoints in hind-and
forelegs was performed with the same electrical pulse. Plasma SS,
VIP, [beta]-endorphin and gastrin were determined by specific
radioimmunoassays. EAP significantly inhibited acid secretion (75%,
p<0.01), which coincided with significant increases in plasma
SS, VIP, [beta]-endorphin and a significant decrease in plasma
gastrin. Naloxone completely reversed EAP-induced inhibition of acid
secretion and changes in plasma concentration of peptides. SAP also
significantly suppressed acid output (30%, p<0.05) with a modest
but significant increase in plasma [beta]-endorphin. However, the
inhibition by EAP on the acid output was significantly greater than
that by SAP (p<0.01). Furthermore, exogenous SS (0.5 [mu]g.kg
-1.h-1 ) significantly inhibited acid output (78%), whereas VIP failed
to inhibit gastric acid secretion. We conclude that in dogs, EAP
significantly inhibits meal-stimulated acid secretion. This acid
inhibition is mediated by the release of [beta]-endorphin and
somatostatin, and an endogenous opiate or opiates appear to play an
important role in the release of SS, VIP and [beta]-endorphin.
Received 19 June 1995; accepted in final form 29 January 1996.
APS Manuscript Number G263-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 March 96