A lot of researches indicate that central nervous system not only exist endogenous opiate analgesic system but also possess endogenous nonopiate analgesic system.The opiate and nonopiate analgesic systems can be selectively activated by defferent environmental or artificial manipulations and modulated the stimulation produced analgesia

acupuncture analgesia and stress-induced analgesia

including the foot shock-induced analgesia

tailshock-produeced analgensia

earshock-induced analgesia

analgesia of cold water swim

analgesia of immobilization or of restraint and analgesia of a-Deoxy-D-glucose and so on.The existance and description of these modulatory mechanisms have it's multiplicity and important clinical implications for the treatment of pain.