[The opiate mechanism of transcranial electroanalgesia in rats and mice]

In partially restrained alert rats and mice, the opioid mechanism of the transcranial electroanalgesia was investigated. Naloxone (0.5-2.0 mg/kg) reversibly suppressed the electroanalgesia in rats. The electroanalgesic effect in rats tolerant to morphine in doses 5-10 mg/kg, was absent. The involvement of endogenous opioid mechanisms in electroanalgesia was confirmed by enhancing of the analgesia with D-phenylalanine (350 mg/kg). The findings suggest that analgesic effect is based on transcranial electrical stimulation of opioid mechanisms. Investigation of endogenous opioid mechanisms in different antinociceptive brain structures in experimental models of transcranial electroanalgesia, is discussed.