Effect of narcotic analgesics on excitatory transmission in the spinal cord

: As demonstrated on nonanesthetized curare-immobilized spinal cats morphine, promedol and fentanyl failed to alter the amplitude of induced potentials in the ventro-lateral columns of the lumbar spinal cord, evoked by a single or repetitive stimulation of the cutaneous or pelvic nerves. In some experiments the same drugs inhibited the nerurons of the posterior horns of the spinal cord activated by the nociceptive stimulation of the peripheral receptors in intraarterial administration of bradykinin. It is suggested that a spinal component was involved in the action of hypnotic analgetics.