Peptide YY receptor in submucosal and myenteric plexus synaptosomes of canine small intestine.
PYY receptors were characterized and their loci determined in canine small intestine. The density of 125I-labeled peptide tyrosine tyrosine (PYY) binding was highest in myenteric (MY) and submucosal (SUB) plexus fractions enriched in synaptosomes. Two binding sites [high affinity (H) and low affinity (L)] were found in the submucosal synaptosome-enriched membrane: dissociation constant (Kd)H = 7.6 pM, maximal binding capacity (Bmax)H = 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 unlabeled PYY. The rate of dissociation was enhanced after exposure of synaptosomes to guanosine 5'-O-(3-thiotriphosphate). Binding of 125I-PYY was completely inhibited by neuropeptide Y (NPY)-(13-36) (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 the presence of Y1 and Y2 receptors in MY. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis 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.
Mao
Y K
YK
Department of Biomedical Science, McMaster University, Hamilton, Ontario, Canada.
Wang
Y F
YF
Ward
G
G
Cipris
S
S
Daniel
E E
EE
McDonald
T J
TJ
D000818:Animals; D001667:Binding, Competitive; D004285:Dogs; D005768:Gastrointestinal Hormones / Q000378:metabolism; D007421:Intestine, Small / Q000294:innervation*; D008970:Molecular Weight; D009197:Myenteric Plexus / Q000378:metabolism*; D009478:Neuropeptide Y / Q000031:analogs & derivatives / Q000378:metabolism; D019894:Peptide YY; D010455:Peptides / Q000378:metabolism; D011964:Receptors, Gastrointestinal Hormone / Q000737:chemistry / Q000378:metabolism*; D012530:Saxitoxin / Q000378:metabolism; D013368:Submucous Plexus / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*; D014018:Tissue Distribution
D005768:Gastrointestinal Hormones; D009478:Neuropeptide Y; D010455:Peptides; D011964:Receptors, Gastrointestinal Hormone; C082172:peptide YY receptor; D019894:Peptide YY; D012530:Saxitoxin