01958nas a2200169   4500008004100000022001400041245009600055210006900151260001200220300001400232490000800246520141700254653002601671100002301697700002101720856004701741       1981                        eng d  a0022-356500aModification of spinal cord transmission by an interaction of chlorpromazine and phenytoin.0 aModification of spinal cord transmission by an interaction of ch  c02/1981  a270–2740 v2163 aCat spinal cord monosynaptic activity during slow repetitive stimulation (0.2 Hz) and post-tetanic potentiation was used to evaluate the combination effects of phenytoin and chlorpromazine. The drug effects were compared in anesthetized cats with either high spinal transection or intact central nervous systems to determine whether the drugs were acting segmentally or suprasegmentally. When chlorpromazine and phenytoin were given in combination to intact animals, the depressant effect on the monosynaptic response was limited to 50% of control, which was not more than the maximum effect of either drug given alone. In spinal animals, chlorpromazine reversed the phenytoin-induced depression during 0.2 Hz stimulation, whereas only the effects of phenytoin on post-tetanic potentiation were evident after the drug combination. These results show that although phenytoin and chlorpromazine each have a depressant effect on spinal cord transmission, the combined effect is limited to a 50% decrease in intact animals. It is suggested that this occlusive drug effect demonstrates that the drug combination has a limited depressant action in the intact nervous system, an action which permits the expression of the effects of these drugs on the other elements of the reflex arc. Collectively, these actions of the drug combination are consistent with their known efficacy in treating certain cases of spasticity.10aSynaptic Transmission1 aCarp, Jonathan, S.1 aAnderson, R., J.  uhttp://www.ncbi.nlm.nih.gov/pubmed/6257885