论文部分内容阅读
Ginsenoside-Rd is one of thepurified pharmacologically active ingredients- the saponins of Panax notoginseng ,atraditional medicinal herb. Previous studies of our laboratory suggested that totalsaponins of panax notoginseng have an inhibitory effect on receptor-operated Ca2+entry.
In vascular smooth muscle cells, two sources of increased cytoplasmic free Ca2+ arerelease from internal intracellular store (mainly sarcoplasmic reticulum,SR) and influxof Ca2+ across the plasma membrane.The ways in which Ca2+entering across theplasma membrane include Ca2+-Na+ exchange, leakage, entry through Ca2+ channelsand non-specific ration channels. Ca2+ channels are the most important ways forCa2+entry into the cytoplasm to provide a sustained increase in cytoplasmic Ca2+.Ca2+ channels can be divided into 1)the voltage-dependent calcium channel (VDCC),which is activated by membrane depolarization; 2)the receptor-operated calciumchannel (ROCC), which is activated by interaction of agonists with respectivereceptors and downstream signaling proteins, including diacylglycerol (DAG),inositol 1,4,5-triphosphate (IP3) and protein kinase C (PKC) etc.; and 3) thestore-operated calcium channel (SOCC), which is activated as a result of depletion ofCa2+ from endoplasmic reticulum.