Propranolol, 14C-morphine accumulation and avoidance: peripheral and central variables.
Pretreatment with propranolol HCI resulted in a substantial reduction in the amount of 14C-morphine found in blood plasma, neostriatum plus adjacent tissue, pons-medulla, midbrain, cerebral cortex and cerebellum 25 min after IP injection of the labelled morphine. Previous observations, demonstrating attenuation of behavioral effects of morphine following pretreatment with propranolol, might have been due to a decrease in peripheral and/or central levels of morphine. However, when morphine HCI (10-20 MUM) was administered via intraventricular cannulae following pretreatment with propranolol given intraperitoneally in rats performing free operant (sidman) avoidance, the anti-avoidance effects of the opiate were also attenuated. Hence, previous results cannot be attributed solely to reduced concentration of morphine at CNS site(s) of action.
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D001921:Brain / Q000378:metabolism; D003216:Conditioning, Operant / Q000187:drug effects; D008297:Male; D009020:Morphine / Q000097:blood / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats
D009020:Morphine; D011433:Propranolol