effects of cholecystokinin receptor antagonists on morphine- and cocaineinduced hypothermia

the effects of cholecystokinin (cck) receptor antagonists on hypothermia induced by cocaine or morphine have been studied in mice. in the present work, subcutaneous (sc) injection of cocaine (50-150 mg/kg) or morphine (125-500 mg/kg) induced hypothermia in mice. administration of ccka receptor antagonist mk-329 (0.5-1.5 mg/kg), cckb receptor antagonist l-365, 260 (0.5-1.5 mgl kg) and cck receptor antagonist proglumide (15-45 mg/kg) 60 min. prior to cocaine injection reduced hypothermia induced by cocaine. mk-329 or proglumide also reduced the morphine response. single administration of mk-329 and l- 365,260 to mice decreased mice core body temperature. it is concluded that the hypothermic effect of cocaine and morphine may be mediated through ccka and cckb receptor mechanism(s).