Nishimaru K, Tanaka Y, Tanaka H, Shigenobu K. Pharmacological evidence for involvement of phospholipase D, protein kinase C, and sodium-calcium exchanger in alpha-adrenoceptor-mediated negative inotropy in adult mouse ventricle.
J Pharmacol Sci 2003;
92:196-202. [PMID:
12890884 DOI:
10.1254/jphs.92.196]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The intracellular signalling pathway for alpha-adrenoceptor-mediated negative inotropy was studied pharmacologically in isolated adult mouse ventricle. The negative inotropy was inhibited by GF-109203X, a nonselective protein kinase C inhibitor. Phorbol 12-myristate 13-acetate also produced sustained negative inotropy, which was inhibited by KB-R7943, a Na(+)/Ca(2+) exchanger inhibitor. The alpha-adrenoceptor-mediated negative inotropy was augmented by RHC-80267, a diacylglycerol lipase inhibitor, but was inhibited either by C(2)-ceramide, a phospholipase D inhibitor, and high concentration of propranolol (50 micro M), which inhibits phosphatidate phosphohydrolase. The inotropy was not affected by U-73122, a phospholipase C inhibitor. Lavendustin-A, a tyrosine kinase inhibitor, also inhibited the negative inotropy. These findings suggest that alpha-adrenoceptor-mediated negative inotropy in adult mouse ventricle is mediated by activation of tyrosine kinase, the phospholipase D-phosphatidate phosphohydrolase pathway, and protein kinase C.
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