Arg-Vasopressin (AVP)has obvious analgesic effect.This effect is not depressed by nalxone (NX)
an antagonist of opiate receptor.It was observed that concentration of Leu-enkephalin (LEK) was decreased and catecholamines (CAS) were elevated in brain by injection of AVP (icv) or by electroacu- puncture (EA).This (?)ndicates that both treatments can influence the metabo- lism of the LEK and CAs.Naloxone can turn the analgesic effect of EA
but can not brock the effect of AVP.The effect of AVP seems to be through the descending inhibitory system or through the subtype of opiate receptor. The analgesic effect of EA is more complicated