Peptide yy receptor in canine small intestine: distribution and
characterization in submucosal and myenteric plexus synaptosomes.
Mao, Y. K., Y. F. Wang, G. Ward, S. Cipris, E. E. Daniel, and T. J.
McDonald.
Dept.of Biomedical Science, McMaster University, Hamilton, Ontario,
Canada, L8N 3Z5., Dept. of Medicine, University of West Ontario,
London, Ontario, Canada
APStracts 3:0009G, 1996.
PYY receptors were characterized and then loci determined in canine
small intestine. The density of 125I-PYY binding was highest in
myenteric (MY) and submucosal (SUB) plexus fractions enriched in
synaptosomes. Two binding sites were found in the submucosal
synaptosome-enriched membrane: KdH 7.6 pM, BmaxH 28 fmol/mg; KdL 0.18
nM, BmaxL 120 fmol/mg protein. The binding of 125I-PYY reached a
maximum within 30 min; dissociation was incomplete in the presence of
unlabelled PYY. The rate of dissociation was enhanced after exposure
of synaptosomes to GTP-[delta]-S. Binding of 125I-PYY was completely
inhibited by [13-36]NPY (in SUB and MY) and by [Leu31.Pro34]NPY (in
MY) but only partially by [Leu31,Pro34]NPY in SUB suggesting the
presence of Y2 receptor in SUB and presence of Y1 and Y2 receptors in
MY. SDS-Page analysis of the PYY receptor complex revealed a
radioactive band at 70 kDa. The PYY receptors in the canine small
intestinal myenteric and submucosal plexus correspond in location to
that of PYY in synaptosomes and, are coupled with G proteins.
Different subtypes are present in different loci.
Received 22 September 1994; accepted in final form 12 December
1995.
APS Manuscript Number G370-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 22 January 96