The effect of ketamine on nerve conduction in isolated sciatic nerves of the toad.

The actions of 100-2500 mug ketamine hydrochloride per ml Ringer solution were examined on the various components of the compound nerve volley of isolated sciatic-tibial nerves of toads. The smaller diameter fibres were blocked first and fibres of progressively larger diameter were blocked with increasing ketamine concentration. A progressive reducton in conduction velocities and amplitude, as well as increasing thresholds, accompanied increased drug contact and concentration. A preliminary trial on human volunteers revealed an apparent loss of pain and thermal sensations following subcutaneous injection.