The action of CNS drugs on an isolated sympathetic nerve preparation of rabbit.

The effect of some centrally active drugs on the transmission of nerve impulses through the isolated cervical sympathetic nerve and superior cervical ganglion of the rabbit has been studied by recording both preganglionic and ganglionic responses to single square wave stimuli. Chlorpromazine, trifluoperazine and haloperidol have a greater axonal depressant action than the known local anaesthetics procaine and xylocaine. Chlordiazepoxide and diazepam are similar in local anaesthetic potency to procaine while meprobamate and sodium pentobarbitone possess only slight axonal depressant properties. Meprobamate, sodium pentobarbitone and possibly diazepam have ganglion blocking properties while procaine, chlorpromazine, trifluoperazine, haloperidol and chlordiazepoxide reduce the ganglion potential by virtue of their preganglionic action.