Effect of Temperature on Potassium Liberation During Nerve Activity

Abstract

The resting loss of K from partially dissected stellar nerves from Loligo pealii is increased by lowering the temperature. Repetitive stimulation of the giant axon for an hour causes an average K loss/impulse of 3 [mu][mu]M/cm2 at 24[degree]C, and of 9 [mu][mu]M/cm2 at 6.1[degree]C. No reabsorption of K is seen during the succeeding rest period. The spike amplitude declines with activity to 0.6 of its initial value and the duration lengthens by a factor of 1.4. No significant recovery occurs during the following period of rest. Correction for the change in spike amplitude indicates that the escape of K at the beginning of stimulation is 3.7 and 11.4 [mu][mu]M/cm2 impulse at the two extremes of temperature. In the leg nerves of the crab, Libinia emarginata, the resting and activity losses of K are increased, while the reabsorption following activity is decreased by lowered temperatures. The K liberated is 10 m[mu]M/g impulse at 6[degree]C as compared to 3 m[mu]M/g impulse obtained earlier at room temperature. Necessary corrections, which are discussed, indicate that the actual values are of the order of three times larger.