The effect of external potassium ion concentration on autonomic neuro-muscular transmission

Abstract

The effect of varying the potassium ion concentration on autonomic neuro-muscular transmission was studied in the vas deferens of the mouse. The smooth muscle cells had resting membrane potentials in normal solution of about 75 mV. The relationship between the membrane potential and the external potassium concentration was close to that predicted by the Nernst equation for external potassium concentrations above 20 mM. The relationship followed the trend predicted by the Goldman equation. The time of decay of the excitatory junction potential (EJP) in response to nervous stimulation decreased to one quarter when the potassium concentration was increased from 0 to 5 times that in normal solut..