Calcium antagonistic effects of Chinese crude drugs: preliminary investigation and evaluation by 45 Ca.

Coronary and other diseases in cardiac or brain blood vessels are considered to be due to the excessive influx of Ca(2+) into cytoplasm. If Ca(2+) channels in cell membrane are blocked by medicines or other substances with considerable calcium antagonistic effects, these diseases might be cured or controlled. The influence of some Chinese crude drugs, including Crocus sativus, Carthamus tinctorius, Ginkgo biloba and Bulbus allii macrostemi on Ca(2+) influx in isolated rat aortas was investigated by using (45)Ca as a radioactive tracer, and their calcium antagonistic effects were evaluated. It can be noted that Ca(2+) uptake in isolated rat aorta rings in normal physiological status was not markedly altered by these drugs, whereas the Ca(2+) influxes induced by norepinephrine of 1.2 micromol/L and KCl of 100 mmol/L were significantly inhibited by Crocus, Carthamus and Bulbus in a concentration-dependent manner, but not by Ginkgo. The results show that extracellular Ca(2+) influx through receptor-operated Ca(2+)channels and potential-dependent Ca(2+)channels can be blocked by Crocus, Carthamus and Bulbus. This implies that these Chinese crude drugs have obvious calcium antagonistic effects.