Chronotropic actions of cholecystokinin octapeptide on the rat heart.
Cholecystokinin octapeptide (CCK-8) administered i.v. to urethane-anaesthetized rats or added to the perfusion stream of isolated rat hearts produced an immediate bradycardia. The size of this response was dose-related. Studies in vivo and in vitro using atropine and propranolol indicated that the response to CCK-8 was largely due to a direct action of the peptide on the heart. N-carbobenzoxy-tryptophan (CBZ-Trp), a cholecystokinin receptor antagonist, abolished the response of the isolated heart to CCK-8. Gastrin I did not produce bradycardia. The receptors on rat heart were similar to the classes of cholecystokinin receptors found in brain and exocrine pancreas in that CCK-8 rather than cholecystokinin tetrapeptide (CCK-4) was the preferred agonist.
Marker
J D
JD
Department of Physiology, University of Adelaide, S.A.
Roberts
M L
ML
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D010477:Perfusion; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012844:Sincalide / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013758:Tetragastrin / Q000494:pharmacology
D013758:Tetragastrin; D001285:Atropine; D011433:Propranolol; D012844:Sincalide