THE GAS EXCHANGE OF NERVE DURING STIMULATION

Abstract

The author describes a modification of Thunberg''s microrespirometer by means of which the O consumption of isolated nerves can be measured with a sensitiveness of 4X10-6 cc. of O (6X10-6 gm.). He measured with this the O consumption and the CO2 output of the lateral line nerve in the dogfish, during rest and during stimulation. With increase in the specific diffusing surface in the smaller nerves there seemed to be a definite tendency toward an increased resting O consumption per gm. of tissue, and towards an increased extra utilization of O during stimulation. In resting nerve the average O consumption per gm. per minute was 0.00135 cc. the elimination of CO2 0.0011 cc. the average respiratory quotient 0.83. During stimulation of the nerve the average extra O used was 0.00021 cc, the average extra CO2 eliminated 0.00016 cc, the respiratory quotient 0.78. The true respiratory quotients are probably higher than those represented by the figures, because of the increasing CO2 tension and the consequent storage of this gas.