Dual effects of cholecystokinin-octapeptide on duodenal motility of urethane-anesthetized rats.
Intravenous administration of cholecystokinin octapeptide (CCK-8) to urethane-anesthetized rats produced both inhibitory and excitatory effects on intestinal motility. The inhibitory effect, evident as a transient relaxation or inhibition of distension-induced reflex contractions, was abolished by adrenoreceptor blockade, guanethidine pretreatment or removal of the celiac ganglion complex, but was hexamethonium-and atropine-insensitive. The excitatory action of CCK-8 was atropine- and hexamethonium-sensitive, while being unaffected by guanethidine pretreatment. Ligation experiments indicated that the excitatory effect of CCK-8 originates from a stimulant action on structures in the upper duodenum/pyloric sphincter from which a propagated contraction travels to the distal duodenum. We conclude that i.v. CCK-8 inhibits small intestinal motility by directly activating sympathetic neurons in the celiac ganglion and initiates a propagated form of intestinal motility by stimulating neural elements in the upper part of the small intestine.
Giuliani
S
S
Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy.
Lippe
I T
IT
Maggi
C A
CA
Meli
A
A
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D004386:Duodenum / Q000187:drug effects*; D015905:Gastric Balloon; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006145:Guanethidine / Q000494:pharmacology; D018738:Hexamethonium; D006584:Hexamethonium Compounds / Q000494:pharmacology; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012844:Sincalide / Q000494:pharmacology*; D014520:Urethane
D000959:Antihypertensive Agents; D006584:Hexamethonium Compounds; D018738:Hexamethonium; D014520:Urethane; D001285:Atropine; D012844:Sincalide; D010646:Phentolamine; D006145:Guanethidine