[Temperature-independence of the effect of osmotic pressure on the inward sodium current in the membrane of isolated spinal ganglion neurons of the rat].
The temperature dependence of the effect of transmembrane osmotic pressure on sodium TTX-sensitive inward current was studied on isolated neurons of rat dorsal root ganglia using intracellular perfusion under voltage clamp conditions. It was found that the effect of transmembrane osmotic pressure on the kinetic parameters of sodium current does not depend on temperature in a wide range (from 8 to 40 degrees C). The apparent values of activation energies for the activation and inactivation processes do not depend on osmolality. The overall results indicate that the most satisfactory way to account for the present observations is to postulate that the effect of transmembrane osmotic pressure is determined by the water flux crossing the membrane. It is supposed that this flux takes place within the protein molecule which forms the sodium channel. The molecular mechanisms of interaction between water pathways and gating are discussed.
D000818:Animals; D005727:Ganglia, Spinal / Q000502:physiology*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D009997:Osmotic Pressure; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013696:Temperature
D007473:Ion Channels; D012964:Sodium
Nezavisimost' vliianiia osmoticheskogo davleniia na vkhodiashchiĭ natrievyĭ tok v membrane izolirovannykh neĭronov spinal'nykh gangliev krys ot temperatury.