ON ROLE OF A CENTRAL ADRENERGIC MECHANISM IN MORPHINE ANALGESIC ACTION

The influence of drugs interfering with brain monoamine metabolism on morphine analgesia of rats was estimated by the tail pressure method. Central adrenergic stimulation produced by apomorphine, cocaine, pyrogallol or amphetamine led to stereotyped behaviour and elevation of the pain threshold. Lower doses of these drugs potentiated morphine analgesic action. Reserpine, iproniazid and disulfiram weakened morphine analgesic action. α‐Methyldopa increased morphine action and (±)‐tryptophan did not influence it significantly. 1969 Royal Pharmaceutical Society of Great Britain