The effects of althesin and thiopentone on sympathetic and baroreflex activity.

In decerebrate rabbits which were mechanically ventilated, both Althesin and thiopentone depressed preganglionic sympathetic activity and arterial pressure. Conduction through central baroreceptor pathways, tested by depressor nerve stimulation, showed a selective inhibition of the heart rate response by both agents. Effects were similar with Althesin injection in animals which were lightly anaesthetized with pentobarbitone. Depression of the arterial pressure and sympathetic components of the baroreceptor reflex was apparent only with high doses.