Home
  >  
Section 41
  >  
Chapter 40,659

Mechanism of inhibitory action of peptide YY on cholecystokinin-induced contractions of isolated dog ileum

Baba, H.; Fujimura, M.; Toda, N.

Regulatory Peptides 27(2): 227-235

1990


ISSN/ISBN: 0167-0115
PMID: 2326499
DOI: 10.1016/0167-0115(90)90041-t
Accession: 040658856

In isolated canine ileal longitudinal muscle preparations, cholecystokinin-octapeptide (CCK-8) produced a concentration-dependent contraction, which was suppressed by peptide YY (PYY) and was abolished by tetrodotoxin and atropine. PYY was approximately 2200-times as potent as CR1505, a CCK-receptor antagonist. PYY opposed the action of CCK-8 to a greater extent than that of nicotine and transmural electrical stimulation. Acetylcholine-induced contractions were not influenced by PYY. It seems likely that the CCK-8-induced ileal muscle contraction is associated with an activation of CCK receptors in cholinergic nerves, which generates nerve action potentials and releases acetylcholine, whereas CCK-8 acts on CCK receptors in gallbladder smooth muscle, producing contractions. It may be concluded that PYY inhibits the action of CCK-8 on ileal muscle strips, by inhibiting the release of acetylcholine from cholinergic nerve terminals. On the other hand, in the gallbladder, PYY does not appear to block cholinergic nerve function.

PDF emailed within 0-6 h: $19.90