| Abstract: | Aconitine causes the appearance of two types of modified channels in the Ranvier node membrane. Channels of the first type are activated at high negative potentials and are inactivated only partly or not at all; their selectivity is sharply reduced: The mean ratio of potassium to sodium permeability is 0.72. The properties of these channels are stable with time. The second type of modified channels lose their conductivity during the action of aconitine, and their kinetic characteristics and region of activation are similar to those of normal sodium channels. They are less selective than normally: the ratio of potassium to sodium permeability is 0.22. The sensitivity of the modified channels to tetrodotoxin is at the same level as that of normal sodium channels.Institute of Cytology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 8, No. 2, pp. 152–160, March–April, 1976. |
