title: [Effect of toxin from the sea anemone Homostichantus duerdemi on the sodium inward current in mammalian neurons].
abstract: The effect of toxin from sea anemone Homostichantus duerdemi (HTX-1) on the inward sodium current was studied on the isolated neurons of spinal ganglia of a rat. The experiments were carried out under conditions of voltage clamp and intracellular perfusion at 20 degree C. HTX-1, when added to the extracellular solution, slowed down the inactivation process of sodium channels with no action on activation process. The dependence of the fraction of modified channels upon the concentration of HTX-1 could be described by Langmuir isotherm with the dissociation constant 1.1 +/- 0.1.10(-7) M (at holding potential --100 mV). HTX-1 caused an increase in the peak of early inward current up to 80%. The binding of HTX-1 with sodium channel was strongly potential-dependent. After a short time of application (up to 5 min) the effect of HTX-1 was completely reversible. However, if the action of the toxin exceeded 30 min, the following washing for 90 min did not lead to pronounced removal of the effect.
mesh_terms: D000818:Animals; D002999:Clone Cells; D003063:Cnidaria; D004305:Dose-Response Relationship, Drug; D005727:Ganglia, Spinal / Q000166:cytology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D008387:Marine Toxins / Q000494:pharmacology*; D009447:Neuroblastoma; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D012615:Sea Anemones; D012964:Sodium / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D008387:Marine Toxins; D012964:Sodium
vernacular_title: Deĭstvie toksina iz aktinii Homostichantus duerdemi na natrievyĭ vkhodiashchiĭ tok v neĭronakh mlekopitaiushchikh.