Xuan B, Liu F, Zhang M Y, Xiao J G
Department of Pharmacology, Nanjing Medical University, People's Republic of China.
J Ocul Pharmacol Ther. 1996 Fall;12(3):331-6. doi: 10.1089/jop.1996.12.331.
The effects of tetrandrine (Tet) on the elevation of intracellular free Ca2+ concentration ([Ca2+]i) induced by glutamate, serotonin and histamine in dissociated rabbit retina cells were studied. The changes of [Ca2+]i were reflected by the fluorescent indicator, Fura-2/AM, employed. In the presence of extracellular Ca2+ (1.3 mM), glutamate, serotonin and histamine significantly increased the [Ca2+]i in a dose-dependent manner. Glutamate (100 microM), serotonin (100 microM) and histamine (200 microM) markedly increased the [Ca2+]i of retina cells by 165%, 126% and 58%, respectively. Tet 30 microM significantly inhibited the increase of [Ca2+]i induced by glutamate (100 microM), serotonin (100 microM) and histamine (200 microM) by 28.0%, 46.8% and 29.0%, respectively. A lower concentration (10 microM) of Tet also produced an inhibitory effect on the increase of [Ca2+]i but was less effective than the Tet 30 microM. In Ca(2+)-free Hank's solution, Tet did not produce a significant inhibitory effect on the increase of [Ca2+]i caused by serotonin and histamine. These results indicate that Tet exercises blocking Ca2+ influx from the extracellular site via NMDA, 5-HT2 and H1-receptor operated Ca2+ channels and has no obvious effect on the Ca2+ release from intracellular Ca2+ stores.
研究了粉防己碱（Tet）对离体兔视网膜细胞中由谷氨酸、5-羟色胺和组胺诱导的细胞内游离钙离子浓度（[Ca2+]i）升高的影响。[Ca2+]i的变化通过所采用的荧光指示剂Fura-2/AM来反映。在细胞外存在Ca2+（1.3 mM）的情况下，谷氨酸、5-羟色胺和组胺以剂量依赖的方式显著增加[Ca2+]i。谷氨酸（100 microM）、5-羟色胺（100 microM）和组胺（200 microM）分别使视网膜细胞的[Ca2+]i显著增加165%、126%和58%。30 microM的Tet分别显著抑制由谷氨酸（100 microM）、5-羟色胺（100 microM）和组胺（200 microM）诱导的[Ca2+]i增加28.0%、46.8%和29.0%。较低浓度（10 microM）的Tet也对[Ca2+]i的增加产生抑制作用，但效果不如30 microM的Tet。在无Ca2+的Hank's溶液中，Tet对由5-羟色胺和组胺引起的[Ca2+]i增加没有产生显著的抑制作用。这些结果表明，Tet通过NMDA、5-HT2和H1受体操纵的Ca2+通道阻断细胞外Ca2+内流，对细胞内Ca2+储存释放Ca2+没有明显影响。
