Fig. 4.13. In the Hodgkin-Huxley model, the process determining the variation of potassium conductance with depolarization and repolarization with voltage clamp.
(A) Movement of n-particles as a response to sudden depolarization. Initially,
an is small and
bn is large, as indicated by the thickness of the arrows. Therefore, the fraction
n of n-particles in the permissive state (inside the membrane) is small. Depolarization increases
an and decreases
bn. Thus
n rises exponentially to a larger value. When four n-particles occupy the site around the channel inside the membrane, the channel opens.
(B) The response of the transfer rate coefficients
an and
bn to sudden depolarization and repolarization.
(C) The response of
n and
n4 to a sudden depolarization and repolarization (
GK
n4 )