Presynaptic depression of synaptic response of Renshaw cells by adenosine 5'-monophosphate.

The action of AMP (adenosine 5'-monophosphate) on synaptic transmission of Renshaw cells has been studied in cats under Dial anaesthesia. AMP applied iontophoretically reversibly reduced synaptic responses of Renshaw cells evoked by stimulation of ventral roots, as well as their spontaneous firing; however, there were no marked effects on discharges of these cells caused by iontophoretic application of acetylcholine, asparatate, and glutamate. On the other hand, AMP had no comparable effect on synaptic responses of dorsal horn interneurones evoked by stimulation of dorsal roots or their spontaneous discharges.