AJP - Gastrointestinal and Liver Physiology, Vol 256, Issue 3 589-G597, Copyright © 1989 by American Physiological Society
Neuropeptide Y augments adrenergic contractions at feline lower esophageal sphincter
H. P. Parkman, J. C. Reynolds, C. P. Ogorek and K. M. Kicsak
Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-4283.
The purpose of this study was to determine the anatomic and physiological
interactions between neuropeptide Y (NPY) and adrenergic transmitters at
the feline lower esophageal sphincter (LES). Intraluminal pressures of the
esophagus, LES, and gastric fundus were recorded in anesthetized cats. In a
separate group of cats, gastroesophageal junctions were removed after
locating the LES manometrically. Adjacent sections were stained with
antibodies for NPY and tyrosine hydroxylase (TH). Indirect
immunofluorescence revealed staining of TH- and NPY-like immunoreactive
(LI) nerves in the circular muscle of the LES. Staining was also present
for NPY-LI in longitudinal muscle, muscularis mucosa, periarterial nerves,
and nerves and cell bodies of the myenteric plexus of the LES. In vivo, NPY
produced a biphasic effect at the LES with an initial contraction (lasting
approximately 30 s) followed by a relaxation (lasting approximately 3 min).
NPY at the dose giving 50% of the maximum response (10(-6) g/kg) induced a
contraction of 14.8 +/- 5.0 mmHg (P less than 0.05) followed by a decrease
of basal LES pressure from 29.2 +/- 4.7 to 19.4 +/- 2.9 mmHg (P less than
0.01). Propranolol and phentolamine had no influence on either effect of
NPY.(ABSTRACT TRUNCATED AT 250 WORDS)
