[Effect of replacing calcium ions with barium ions in studies of the inward currents of mammalian neurons].
The effect of replacement of Ca2+ ions by Ba2+ ions in the external artificial solution on a high-threshold calcium current of the somatic membrane of rat dorsal root ganglion neurons was studied by intracellular dialysis technique and voltage clamp method. The conductance of the corresponding channels for Ba2+ ions assessed by the increase in the maximal current amplitude was shown to increase about twice. The decrease of the maximal current amplitude in the course of dialysis associated with the washout of the intracellular content slowed down considerably, probably, due to the removal of the blocking effect of intracellular Ca2+ on the calcium channels. The link of high-threshold calcium channels with cyclic nucleotide metabolism was not disturbed after the replacement of Ca2+ by Ba2+. The data obtained are discussed within the framework of existing ideas about the functioning of calcium channels in excitable membranes.
D000818:Animals; D000831:Animals, Newborn; D001464:Barium / Q000378:metabolism / Q000494:pharmacology*; D002118:Calcium / Q000502:physiology*; D000242:Cyclic AMP / Q000502:physiology; D005727:Ganglia, Spinal / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D009431:Neural Conduction / Q000187:drug effects; D051381:Rats
D007473:Ion Channels; D001464:Barium; D000242:Cyclic AMP; D002118:Calcium
Effekt zameny ionov kal'tsiia ionami bariia pri issledovanii vkhodiashchikh tokov neĭronov mlekopitaiushchikh.