title: Intraperitoneal injection of cholecystokinin elicits sleep in rabbits.
abstract: Cholecystokinin (CCK) reduces food intake and promotes non-rapid-eye-movement sleep (NREMS) in rats. The purpose of present experiments was to determine if CCK is somnogenic in rabbits; another species in which CCK suppresses feeding. White New Zealand rabbits were treated intracerebroventricularly (ICV; 0.05, 0.5 and 2 micrograms) or intraperitoneally (IP; 2.5, 10 and 40 micrograms/kg) with CCK or saline, and sleep-wake activity and brain temperature (Tbr) were recorded for 6 h. Injections of 10 and 40 micrograms/kg CCK IP elicited a decrease in wakefulness and an increase in NREMS during the first hour postinjection. The hypnogenic effects were accompanied by a decrease in Tbr. After the IP injection of a lower dose (2.5 micrograms/kg) a slight, nonsignificant increase in NREMS during the first hour postinjection was followed by a decrease in NREMS. ICV injections of CCK had relatively small inhibitory effects on sleep. We conclude that circulating, hormone CCK might be a hypnogenic signal with a peripheral site of action.
authors.affiliation: Department of Physiology and Biophysics, University of Tennessee, Memphis 38163.
authors.forename: L
authors.initials: L
authors.lastname: Kapás
authors.forename: F
authors.initials: F
authors.lastname: Obál
authors.forename: M R
authors.initials: MR
authors.lastname: Opp
authors.forename: L
authors.initials: L
authors.lastname: Johannsen
authors.forename: J M
authors.initials: JM
authors.lastname: Krueger
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000502:physiology; D002766:Cholecystokinin / Q000008:administration & dosage / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D008297:Male; D011817:Rabbits; D012890:Sleep / Q000187:drug effects*; D012894:Sleep Stages / Q000187:drug effects; D012895:Sleep, REM / Q000187:drug effects; D014851:Wakefulness / Q000187:drug effects
chemical_list: D002766:Cholecystokinin