Effects of cholecystokinin octapeptide on contractile motility of guinea pig common bile duct.
Cholecystokinin octapeptide (CCK-8)-induced contraction and [3H]acetylcholine ([3H]-ACh) release from the longitudinal muscle strip of the guinea pig common bile duct were studied by a standard organ bath method and superfusion system. CCK-8 (10(-7) M) caused a biphasic contraction, a rapid phasic contraction followed by a fading tonic contraction. Hexamethonium, propranolol, and phentolamine had no effects on CCK-8-evoked contraction. Atropine or tetrodotoxin significantly reduced CCK-8-evoked initial phasic contraction and produced a rightward shift of the dose-response curve for CCK-8 (10(-10)-3 x 10(-7) M). CCK-8 provoked a significant [3H]ACh release in a dose-dependent manner, which was almost completely abolished by tetrodotoxin or Ca2+-free medium. These results suggest that CCK-8 receptors are present not only on the smooth muscle cells but also on the intramural cholinergic nerve cell bodies of the guinea pig common bile duct.
Takahashi
T
T
Second Department of Surgery, Hyogo College of Medicine, Japan.
Kusunoki
M
M
Kantoh
M
M
Yamamura
T
T
Utsunomiya
J
J
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D003135:Common Bile Duct / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D012844:Sincalide / Q000494:pharmacology*
D002217:Carbachol; D012844:Sincalide