Electrophysiological studies on the effects of opiates on dorsal horn nociceptive neurones at 51 atmospheres absolute.

The purpose of this study was to investigate the effects, if any, of high pressure on opiate analgesia. The interaction of high pressure with intrathecal morphine (2.5-15 micrograms) and pethidine (10-145 micrograms) was studied on the responses of 51 dorsal horn neurones in the intact rat under urethane anaesthesia to electrical stimulation applied to their receptive fields.