title: [The role of cations from the external medium in regulating the intracellular Ca++ ion concentration in ureteral smooth muscle cells].
abstract: Intracellular concentration of Ca++ ions was determined by the isotope analysis method for the guinea-pig ureter smooth muscle cells in solutions containing Ca++, Na+ and Li+. It was shown that the Ca++ concentration in muscles incubated in Na(+)-free solution containing 2.5 to 15 mmol/l Ca++, reached the maximal value during the period in which spikes were recorded. In the muscles enriched by calcium, intracellular Ca++ concentration was reduced by over 2.5 times in solutions containing Na+ and Ca++ ions (120 mmol/l and 10 mmol/l, resp.,) as compared with Na(+)-free medium. The reducing of calcium content was mainly obvious during first 5 min. Na+ ions were not specific for calcium removal from cells, Li+ ions being able to substitute them in this process. The findings suggest a possible participation of Na(+)-Ca(++)-exchange mechanism in the maintenance of the calcium homeostasis in the ureter smooth muscle cells.
authors.forename: K V
authors.initials: KV
authors.lastname: Kazarian
authors.forename: A S
authors.initials: AS
authors.lastname: Oganesian
authors.forename: G A
authors.initials: GA
authors.lastname: Gevorkian
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology* / Q000502:physiology*; D002413:Cations, Divalent; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry; D006168:Guinea Pigs; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008094:Lithium / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D010477:Perfusion / Q000379:methods; D012964:Sodium / Q000494:pharmacology*; D014513:Ureter / Q000187:drug effects / Q000502:physiology
chemical_list: D002413:Cations, Divalent; D008094:Lithium; D012964:Sodium; D002118:Calcium
vernacular_title: Rol' kationov vneshneĭ sredy v reguliatsii vnutrikletochnoĭ kontsentratsii ionov Ca++ v gladomyshechnykh kletkakh mochetochnika.