Lodge N J
J Mol Cell Cardiol. 1986 Nov;18(11):1157-64. doi: 10.1016/s0022-2828(86)80041-4.
The effect of high K+/low Na+-Tyrode's solution on Ca2+ uptake into neonatal rat atrium was studied using 45Ca2+. Substitution of 60-129 mM Na+ in Tyrode's solution by equimolar concentrations of K+ or choline, significantly (with the exception of 60 mM choline substitution) increased Ca2+ uptake above control. Furthermore, the Ca2+ uptake stimulated by K+ substitution was significantly greater than that stimulated by choline substitution at the corresponding concentrations. The choline/low Na+-induced Ca2+ uptake (i.e. that above the Ca2+ uptake measured in normal Tyrode's solution) was increased by pre-exposure to either ice-cold Tyrode's solution for 1 h (approximately 36% increase) or to K+-free Tyrode's solution for 3 h (approximately 100% increase). The choline/low Na+-induced Ca2+ uptake was abolished by the hypertonic addition of NaCl (returning the bathing Na+ concentration to normal), increased (approximately 140%) by the addition of 1.8 mM PO4(3-)-free Hepes buffered choline/low Na+ media, but unaffected by 0.2 mM cadmium. The high K+/low Na+-induced Ca2+ uptake (i.e. that above the Ca2+ uptake measured in normal Tyrode's solution) was relatively insensitive to pre-exposure to cold (0% change) or K+-free media (11% increase) and only 50% inhibited by the hypertonic addition of NaCl (returning the bathing Na+ concentration to normal). However, the high K+/low Na+-induced Ca2+ uptake was 57% inhibited by 0.2 mM cadmium and approximately 30% inhibited by the addition of 1.8 mM PO4(3-) to HCO3-/PO4(3-)-free Hepes buffered high K+/low Na+ media.(ABSTRACT TRUNCATED AT 250 WORDS)
采用⁴⁵Ca²⁺研究了高钾/低钠-台氏液对新生大鼠心房摄取Ca²⁺的影响。用等摩尔浓度的钾或胆碱替代台氏液中60 - 129 mM的钠，显著增加了Ca²⁺摄取（60 mM胆碱替代除外），高于对照组。此外，在相应浓度下，钾替代刺激的Ca²⁺摄取显著大于胆碱替代刺激的Ca²⁺摄取。预先暴露于冰冷台氏液1小时（增加约36%）或无钾台氏液3小时（增加约100%），可增加胆碱/低钠诱导的Ca²⁺摄取（即高于正常台氏液中测得的Ca²⁺摄取）。高渗添加氯化钠（使浴液钠浓度恢复正常）可消除胆碱/低钠诱导的Ca²⁺摄取，添加1.8 mM无磷酸根的HEPES缓冲胆碱/低钠培养基可使其增加（约140%），但不受0.2 mM镉的影响。高钾/低钠诱导的Ca²⁺摄取（即高于正常台氏液中测得的Ca²⁺摄取）对预先暴露于寒冷环境（变化0%）或无钾培养基（增加11%）相对不敏感，高渗添加氯化钠（使浴液钠浓度恢复正常）仅使其抑制50%。然而，0.2 mM镉可使高钾/低钠诱导的Ca²⁺摄取抑制57%，向无HCO₃⁻/PO₄³⁻的HEPES缓冲高钾/低钠培养基中添加1.8 mM PO₄³⁻可使其抑制约30%。（摘要截于250字）
