The effects of althesin on arterial pressure, pulse rate preganglionic sympathetic activity and barostatic reflexes in cats.

We have studied the effects of Althesin on preganglionic cervical sympathetic nervous activity, arterial pressure, pulse rate and barostatic reflexes in cats. Normal, baroreceptor denervated and decerebrate animals were studied. On the basis of our finding it is concluded that Althesin severely depresses sympathetic nervous activity by action on the vasomotor centre. The depression of arterial pressure however was only moderate due to two compensatory mechanisms: a vagolytic action of Althesin and a peripheral vascular effect believed to be caused by an enhanced action of catecholamines caused by Althesin. Barostatic reflexes were found active under conditions where Althesin did not totally abolish sympathetic tone.