5-羟色胺对培养胃底平滑肌细胞内游离钙动员的影响

Mechanism of 5-hydroxytryptamine on introcellular calcium dynamics in stomach fundus smooth muscle cells of rats

目的 研究 5 - HT诱导胃底平滑肌细胞内钙动员的机制 .方法 采用 Ca2 +指示剂 Fluo- 3/ AM作为细胞内钙离子的荧光探针负载培养的胃底平滑肌细胞 ,共聚焦技术检测细胞内钙荧光强度的变化 .结果 基础状态下 SFSMC[Ca2 + ]i 荧光强度 (FI)为 2 6 4± 15 ,5 - HT 10μmol· L- 1 使荧光强度的变化 ΔFI为 16 .5± 2 .6 ;细胞外无钙时 ,5 - HT升高[Ca2 + ]作用被减弱 ,但除去细胞外钙 ,并使用内罗啶 (ryan-odine)孵育后 ,5 - HT 不再引起荧光强度的变化 ;10μmol· L- 1 米安舍林 (mianserin)可部分拮抗 5 - HT升高[Ca2 + ]i 的作用 ,赛更定 (cyprohetadine)不能抑制 5 - HT升高的胞内钙 ;Mn92 0 2和拉西地平 (lacidipine)均能完全抑制 5 -HT升高 [Ca2 + ]i 的作用 .结论 5 - HT可通过促进外钙内流及钙池 (SR)释放使 [Ca2 + ]i 升高 ;在胃底平滑肌 5 - HT升高胞内钙部分通过 5 - HT2 受体 ,而不是通过 5 - HT1 C受体 ;5 -羟色胺通过 L型钙通道促外钙内流 ;二氢吡啶类钙拮抗剂能通过阻滞 L 型钙通道 ,而完全抑制 5 -

AIM To study the mechanism of 5 HT on [Ca 2+ ] i dynamics in stomach fundus smooth muscle cells (SFSMC) of rats. METHODS Cells were cultured and loaded with Fluo 3/AM. [Ca 2+ ] i was measured by fluorescent intensity (FI) in each cell with confocal microscopy. RESULTS Resting FI level of SFSMC was 264±15, 10 μmol·L -1 5 HT elevated [Ca 2+ ] i, the change of FI was 16.5± 2.62; When extracellular Ca 2+ was removed,a decrease in resting level and a small, transient increase in [Ca 2+ ] i were observed. In D Hanks solution with ryanodine, 5 HT had no effect on basal levels of [Ca 2+ ] i. The effect of 5 HT was partly inhibited by 10 μmol·L -1 mianserin, but cyprohetadine had no effect on 5 HT. When pretreated with Mn9202 or lacidipine, the effects of 5 HT were throughly inhibited. CONCLUSION Data suggest that 5 HT acts by 5 HT 2 receptors on SFSMC to cause Ca 2+ to release from introcellular stores, followed by Ca 2+ influx, possibly through L type calcium channels. And Mn9202 has the complete antagonist effect on 5 HT.