Neuronal regulation of the release and action of secretin-releasing
peptide and secretin.
Li, P., Tm Chang, Wy Chey.
Center for Digestive and Liver Diseases, Division of
Gastroenterology and Hepatology, Department of Medicine, University
of Rochester School of Medicine and Dentistry, Rochester, NY
APStracts 2:0070G, 1995.
The acid-stimulated release of secretin is mediated by a secretin
releasing peptide (SRP) in rats. In the present study we investigated
to determine whether the neural mechanism(s) is involved in the
regulation of release and action of SRP in anesthetized rats. A
concentrated acid perfusate (CAP) containing SRP was obtained from
donor rats. CAP administered into recipient rats significantly
increased pancreatic flow volume (81.6 +/-18.3%), bicarbonate output
(188.7 +/- 15.6%) and plasma secretin level (from 0.9 +/- 0.2 to 4.4
+/- 0.5 pM). However, this effect was attenuated by the CAP from
donor rats pretreated with tetrodotoxin (TTX), propranolol, bilateral
subdiaphragmatic vagotomy (BSV), or systemic and topical
administration of capsaicin. In contrast, the CAP from donor rats
pretreated with phentolamine, atropine or hexamethonium did not alter
the increase in plasma secretin concentration and pancreatic
secretion. Moreover, the action of CAP on secretin release was
significantly inhibited in the recipient rats pretreated with TTX,
BSV and topical applications of capsaicin, but it was not suppressed
in the recipient rats pretreated with atropine, hexamethonium or
propranolol. Furthermore, perivagal and duodeno-jejunal mucosal
application of capsaicin abolished the pancreatic secretory response
to secretin at 5 pmol/kg/h. In conclusion, the release and action of
both SRP and secretin are mediated by vagal afferent pathway. [beta]
-adrenergic receptor also plays a significant role in the release of
SRP.
Received 5 January 1995; accepted in final form 21 March 1995.
APS Manuscript Number G009-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.