The Effects of Methoxyflurane on Arterial Pressure, Preganglionic Sympathetic Activity and Barostatic Reflexes

The effects of methoxyflurane on arterial pressure and cervical pregangiionic sympathetic activity and the responses of these to stimulation of the aortic depressor nerve were studied in cats. In normal cats end-expired concentrations of methoxyflurane of 0.28, 0.48 and 0.55 per cent produced proportional depressions in arterial pressure. Sympathetic activity was unaffected. The responses of arterial pressure and sympathetic activity to baroreceptor nerve stimulation also were unaffected by methoxyflurane in these concentrations. In baroreceptor-denervated animals methoxyflurane produced a slight reduction in sympathetic activity, believed to be due to a depressant action on the medullary pressor neurons, an action which in normal animals is counteracted by the reflex response to arterial hypotension.