title: [Effect of the medium composition on the resting membrane potential in the earthworm longitudinal somatic muscle fibers].
abstract: Norepinephrine or increased extracellular K+ hyperpolarize the membrane of the earthworm somatic muscle fibre, whereas removal of Cl- from external solution or a hypotonic solution depolarize the membrane. The dependence of the membrane resting potential on the extracellular K+ is quite characteristic against the background of ouabain action. A preliminary membrane depolarisation by ouabain eliminates the above effects on the membrane resting potential. The data obtained suggest that the ouabain-sensitive active ion pump directly contributes to the membrane resting potential value. This hypothesis is discussed with respect to existence of active Cl- transport combined with Na+, K(+)-pump which presumably takes part in the intracellular osmotic pressure regulation in the earthworm somatic muscle.
authors.affiliation: Kazan State Medical University.
authors.forename: E M
authors.initials: EM
authors.lastname: Volkov
authors.forename: L F
authors.initials: LF
authors.lastname: Nurullin
authors.forename: E E
authors.initials: EE
authors.lastname: Nikol'skiĭ
mesh_terms: D000818:Animals; D001692:Biological Transport; D002712:Chlorides / Q000378:metabolism; D003470:Culture Media; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D009835:Oligochaeta; D011895:Rana ridibunda
chemical_list: D002712:Chlorides; D003470:Culture Media; D007473:Ion Channels