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The effect of ligustrazine on L-type calcium current, calcium transient and contractility in rabbit ventricular myocytes

Authors Ren, Zhiqiang; Ma, Jihua; Zhang, Peihua; Luo, Antao; Zhang, Shuo; Kong, Linghao; Qian, Chunping

Journal JOURNAL OF ETHNOPHARMACOLOGY , DEC 18 2012,3:144

DOI 10.1016/j.jep.2012.09.037 PubMed 23058991

Abstract Ethnopharmacological relevance: Ligustrazine, the biologically active ingredient isolated from a popular Chinese medicinal plant, Ligusticum chuanxiong Hort. (Umbelliferae), has been used effectively to treat ischemic heart diseases, cerebrovascular and thrombotic vascular diseases since the 1970s.Materials and methods: At present, the effect of ligustrazine on L-type calcium current (ICa-L) of ventricular myocytes remains controversial. In this study, we use the whole-cell patch-clamp techniques and video-based edge detection and dual excitation fluorescence photomultiplier systems to study the effects of ligustrazine on ICa-L, and calcium transient and contractility in rabbit ventricular myocytes in the absence and presence of isoprenaline (ISO).Results: Ligustrazine (5 mu M) in low concentration did not affect ICa-L (P > 0.05), higher concentrations of this drug (10, 20, 40, 80 mu M) inhibited ICa-L in a concentration-dependent manner and reduced ICa-L by 9.6 +/- 2.9%, 21.0 +/- 4.3%, 33.9 +/- 43%, and 51.6 +/- 7.3%, respectively. Under normal conditions, ligustrazine (40 mu M) reduced baseline of fura-2 fluorescence intensities (FFI, 340/380 ratio), namely diastolic calcium concentration, changes in FFI (Delta FFI, 340/380 ratio) and maximal velocity of Ca2+ rise and decay (340/380 ratio/ms) by 6.3%, 26.1%, 25.2%, and 26.5%, and decreased sarcomere peak shorting (PS) and maximal velocity of shorting and relengthening by 36.4%, 31.9%, and 25.0%, respectively. Similarly, ligustrazine (40 mu M) reduced baseline FFI, Delta FFI, and maximal velocity of Ca2+ rise and decay by 14.1%, 51.1%, 35.2%, and 41.1%, and reduced sarcomere PS and maximal velocity of shorting and relengthening by 38.6%, 50.0% and 39.1%, respectively, in the presence of ISO.Conclusions: Ligustrazine not only significantly inhibits ICa-L in a concentration-dependent manner but also suppressed calcium transient and contraction in the absence and presence of ISO. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

Species covered 川芎 Ligusticum chuanxiong