IMMOBILIZATION OF INTRAMEMBRANE CHARGE IN MYXICOLA GIANT-AXONS

1. Immobilization of gating charge was examined in Myxicola giant axons dialysed with Cs+. 2. With increasing pulse durations the ratio QOFF/QON decreases to as little as 0.25 with a time constant of 3.2 msec determined from composite data. Na inactivation time constants measured in the same axons ranged from 0.8 to 1.5 msec. A slow component of QOFF tends to appear as QOFF/QON decreases. 3. Both QON and QOFF may be decreased by a prepulse with no change in their time course. In this case the time course of the decrease is similar to that observed for INA. 4. The normalized steady‐state charge immobilization curve is shifted in the depolarized direction by 15‐‐20 mV from the normalized Na inactivation curve. © 1979 The Physiological Society