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用荧光染色法观察了合成的大鼠降钙素基因相关肽（ＣＧＲＰ）对大鼠心肌细胞内游离Ｃａ￣（２＋）含量的影响。结果证明，ＣＧＲＰ能明显增加心肌细胞内Ｃａ￣（２＋）含量，小、中和大剂量（１０￣（－９）、１０￣（－８）、１０￣（－７）ｍｏｌ／Ｌ）的ＣＧＲＰ使Ｃａ￣（２＋）含量分别增加至２７６．８８±６．３１、３６４．９９７±１２．７０、５７６．３９７±１５ｎｍｏｌ／Ｌ与对照组（１３６．２８±７．２４ｎｍｏｌ／Ｌ）相比差异非常显著（Ｐ＜０．０１），且随着ＣＧＲＰ剂量的增加而作用明显加强，呈现剂量—效应关系。３０μｍｏｌ／Ｌ的维拉帕米对ＣＧＲＰ所致的细胞内Ｃａ￣（２＋）增加有抑制作用，对小、中、大剂量ＣＧＲＰ作用的抑制率分别为４８％、４４％和１８％。我们推测，ＣＧＲＰ可能直接作用于心肌细胞。低浓度ＣＧＲＰ的正性肌力作用主要是促进Ｃａ￣（２＋）经Ｃａ￣（２＋）通道内流，使心肌细胞内Ｃａ￣（２＋）含量增加的结果。在大剂量ＣＧＲＰ的正性肌力作用中Ｃａ￣（２＋）内流也起到一定作用。
Fluorescent staining was used to observe the effect of synthetic CGRP on the content of free calcium in rat cardiomyocytes. The results demonstrated that CGRP significantly increased Ca 2+ content in myocardial cells, while small, medium and high doses of CGRP (10 -9, 10 -8, 10 -7 mol / L) The content of Ca ~ (2+) increased to 276.88 ± 6.31,364.997 ± 12.70,576.397 ± 15nmol / L compared with the control group (136.28 ± 7.24nmol / L) (P <0.01). With the increase of CGRP dose, the effect was significantly enhanced, showing a dose-response relationship. 30μmol / L verapamil inhibited CGRP-induced increase of intracellular Ca 2+, and 48%, 44% and 18% inhibition of small, medium and large doses of CGRP respectively. We speculate that CGRP may act directly on cardiomyocytes. The positive inotropic effect of low concentration of CGRP is mainly to promote Ca ~ (2+) influx through Ca ~ (2+) channel and increase the content of Ca ~ (2+) in cardiomyocytes. Ca ~ (2+) influx also plays a role in the positive inotropic action of large doses of CGRP.