title: Effects of cholecystokinin, gastrin, and related peptides on coho salmon gallbladder contraction in vitro.
abstract: Isometric contractions of coho salmon (Oncorhynchus kisutch) gallbladder longitudinal muscle strips were recorded in response to porcine cholecystokinin (CCK), octapeptide of CCK (OP-CCK), desulfated octapeptide of CCK (ds-OP-CCK), porcine heptadecapeptide gastrins I and II, and pentagastrin. Peak tonic contraction amplitude and peak rhythmic contraction frequency were used to construct concentration-response curves for each peptide. Observed maximal responses to each peptide were not significantly different; therefore, all peptides tested were equal in efficacy. CCK, OP-CCK, and gastrin II were equipotent, and ds-OP-CCK and gastrin I were equipotent.
  
  
  CONCLUSIONS
  1) porcine CCK can stimulate contraction of the coho salmon gallbladder; 2) tonic and rhythmic contractile responses are elicited in coho salmon gallbladder by agonists; 3) coho salmon gallbladder muscle cannot distinguish between agonists that differ in the location of a sulfated tyrosyl residue at position 6 versus position 7 from the C-terminus; and 4) the results of this study are consistent with the hypothesis that coho salmon gallbladder muscle contains a relatively primitive CCK receptor.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002766:Cholecystokinin / Q000494:pharmacology*; D005260:Female; D005704:Gallbladder / Q000187:drug effects* / Q000502:physiology; D005755:Gastrins / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010418:Pentagastrin / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D010802:Phylogeny; D012474:Salmon / Q000502:physiology*; D013045:Species Specificity; D013329:Structure-Activity Relationship
chemical_list: D005755:Gastrins; D010455:Peptides; D001285:Atropine; D002766:Cholecystokinin; D010418:Pentagastrin; D000109:Acetylcholine