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Three rhesus monkeys Macaca mulatta, formerly dependent on morphine, had increased sensitivity to nalorphine's effect of suppressing operant responding for food, as compared with two monkeys with no history of morphine exposure. Within the dose range employed, nalorphine injections produced emesis, salivation, and hyperirritability in formerly morphine-dependent monkeys but not in controls.

A combination of droperidol and fentanyl produces qualitatively similar pharmacologic effects in dogs and primates. Unlike the dog, however, primates did not appear to respond to auditory stimuli. As a result of the analgesic and sedative or tranquil state produced in primates, the animals were easily handled and tolerant of painful stimuli. The principal desirable features of the combination were high analgesic and sedative potency and a rapid onset of action following intramuscular administration. High doses produced respiratory depression. However, this effect was easily reversed by administering nalorphine hydrochloride.

(1) Acute morphine treatment of rats reduced the total catecholamine content as well as the noradrenaline content of the adrenal gland. This was accompanied by increased ATPase activity and increased calcium content of the medullary cells. (2) After chronic morphine treatment, the total catecholamine content remained more or less unaltered, but the noradrenaline content was markedly increased together with the noradrenaline-containing areas, in comparison with what was observed in control animals. The ATPase activity of the medullary cells was found to be diminished along with the decreased calcium content. (3) In nalorphine-induced abstinence, a decrease in total catecholamine content together with a reduction of noradrenaline content and of noradrenaline-containing areas were observed. ATPase activity was also found to be increased with increased calcium content.