Ethanol augments the baroreflex-inhibitory effects of sciatic nerve stimulation in the anaesthetized dog

Electrical stimulation of somatic afferent fibres in the sciatic nerve has been used as a model of injury in the anaesthetized dog. Stimulation of the sciatic nerve (during reflexly induced periods of apnoea to obviate any respiratory effects of sciatic stimulation) led to a simultaneous increase in arterial blood pressure and heart rate and a decrease in baroreflex sensitivity. Infusion of ethanol sufficient to produce clinically relevant plasma ethanol levels (100-200 mg %) had no consistent effects on baroreflex sensitivity, but enhanced the pressor response and significantly augmented the inhibitory effects of sciatic stimulation on the baroreflex. Since ethanol is commonly associated with injury in man, such changes in the response to 'injury' may modify the patients' cardiovascular response to the injury and complicate diagnosis.