Inhibition of bradykinin-induced phosphoinositide hydrolysis and Ca2+ mobilisation by phorbol ester in rat cultured vascular smooth muscle cells

Chuen Mao Yang, Yih Jeng Tsai, Shiow Lin Pan, Chih Chung Lin, Wen Bin Wu, Chuan Chwan Wang, Samuel C.M. Huang, Chi Tso Chiu

研究成果: 雜誌貢獻文章同行評審

5 引文 斯高帕斯(Scopus)

摘要

Regulation of the increase in inositol phosphate (IP) production and intracellular Ca2+ concentration ([Ca2+](i) by protein kinase C (PKC) was investigated in cultured rat vascular smooth muscle cells (VSMCs). Pretreatment of VSMCs with phorbol 12-myristate 14-acetate (PMA, 1 μM) for 30 min almost abolished the BK-induced IP formation and Ca2+ mobilisation. This inhibition was reduced after incubating the cells with PMA for 4 h, and within 24 h the BK-induced responses were greater than those of control cells. The concentrations of PMA giving a half-maximal (pEC50) and maximal inhibition of BK induced an increase in [Ca2+](i), were 7.8 ± 0.3 M and 1 μM, n = 8, respectively. Prior treatment of VSMCs with staurosporine (1 μM), a PKC inhibitor, inhibited the ability of PMA to attenuate BK-induced responses, suggesting that the inhibitory effect of PMA is mediated through the activation of PKC. Paralleling the effect of PMA on the BK-induced IP formation and Ca2+ mobilisation, the translocation and downregulation of PKC isozymes were determined by Western blotting with antibodies against different PKC isozymes. The results revealed that treatment of the cells with PMA for various times, translocation of PKC-α, βI, βII, δ, ε, and ζ isozymes from the cytosol to the membrane were seen after 5 min, 30 min, 2 h, and 4 h of treatment. However, 24-h treatment caused a partial downregulation of these PKC isozymes in both fractions. Treatment of VSMCs with 1 μM PMA for either 1 or 24 h did not significantly change the K(D) and B(max) of the BK receptor for binding (control: K(D) = 1.7 ± 0.2 nM; B(max) = 47.3 ± 4.4 fmolmg protein), indicating that BK receptors are not a site for the inhibitory effect of PMA on BK-induced responses. In conclusion, these resuts demonstrate that translocation of PKC-α, βI, βII, δ, ε, and ζ induced by PMA caused an attenuation of BK-induced IPs accumulation and Ca2+ mobilisation in VSMCs. Copyright (C) 1999 Elsevier Science Inc.
原文英語
頁(從 - 到)899-907
頁數9
期刊Cellular Signalling
11
發行號12
DOIs
出版狀態已發佈 - 12月 1999
對外發佈

ASJC Scopus subject areas

  • 細胞生物學

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