Efferent Impulses in the Splanchnic Nerve

Summary. Efferent impulses were observed in the splanchnic nerve of the cat, sometimes continuous, sometimes synchronous with respiration or with the heart beats. During asphyxia the amplitude of the impulses increased greatly. If artificial respiration was resumed, the electric activity quickly diminished and for a while nearly disappeared. Oxygen want led to an increase in the potentials, and pure oxygen to a decrease. Both these effects disappeared after the elimination of the buffer nerves. Accumulation of carbon dioxide caused greater activity in the nerve before as well as after section of the sinus and vagodepressor nerves. Bleeding, or the injection of acetylcholine, led to a remarkable increase in the potentials, whereas adrenaline gave rise to a diminution or even the disappearance of the impulses. After denervation of the sinus and aorta mechanisms, the effect of adrenaline was very small at normal blood pressure but fairly great at low level. Section of the sinus and vagodepressor nerves greatly increased the electric activity of the splanchnic nerve. The results are interpreted as being due to reflex influence from the chemo‐ and pressoreceptors of the sinus‐ and aorta mechanisms and to a central effect from carbon dioxide accumulation.