Contributions of various ions to the resting and action potentials of crayfish medial giant axons.

摘要: The membrane of crayfish medial giant axons is permeable at rest to ions in the rank K>Na>Ca>Cl. With K present, variation other has little or no effect, but with absent axon hyperpolarizes when Na reduced eliminated by replacement Tris (slope ca. 30 mV/decade Na0). hyperpolarization independent presence Cl its absence (substitution methanesulfonate isethionate). resistance increases progressively as removed. These changes persist after spike blocked tetrodotoxin. An increase Ca causes depolarization 20 mV/decade) provided K, and are all absent, there change potential on increasing 150mm. induced associated an increased resistance. Spike electrogenesis involves activation well activation, after-depolarization end due a conductance for Ca. Two alternative equivalent circuits resting active discussed.