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Effects of growth hormone‐releasing peptide on [Ca 2+ ]i and NO in rat cardiomyocytes
Author(s) -
Tian Guozhong,
Li Meixiu,
Zhong Zhenya,
Bai Shuling,
Kang YuMing
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.626.3
Subject(s) - medicine , contractility , chemistry , endocrinology , hormone , stimulation , calcium , perfusion , biology
Growth hormone‐releasing peptide (GHRP) is an oligopeptide which can promote the release of growth hormone. GHRP has protective effects on the heart. We observed the effects of GHRP on subcellular Ca 2+ and NO dynamics of the cardiomyocytes in Sprage‐Dawley rats. Cardiomyocytes were isolated by the constant‐flow Langendorff system and enzymic methods. Effects of GHRP on [Ca 2+ ]i and NO in crdiomyocytes of rats were observed by LSCM after [Ca 2+ ]i and NO of cardiomyocytes were double‐labeled by molecular probes. GHRP induced a transient increase of [Ca 2+ ]i then followed by a plateau phase in the cardiomyocytes of normal rats, the similar response was found in the heart failure (HF) rats. Acute ejection of adriamycin (ADR) into perfusion solution induced an abnormal elevation of the fluorescence intensity of [Ca 2+ ]i in normal cardiomyocytes, GHRP moderately reduced the elevation and decreased the Ca 2+ oscillation rate. There was no change in NO signal after ADR stimulation. Rhod‐2/AM and DAF‐FM/DA could act as [Ca 2+ ]i and NO molecular probes respectively. GHRP increased [Ca 2+ ]i of crdiomyocytes in both HF rats and normal rats. GHRP has an inhibitory effect on calcium overload caused by ADR. GHRP has bidirectional modulatory effects on cardiac contractility. Both GHRP and ADR did not affect NO signal in cardiomyocytes of rats.