- 作者: Chuen-Mao Yang; Ming-Che Hsu; Richard Ong; Jen-Tsung Hsieh; Hui-Liang Tsao; Yi-Chin Chen; Shue-Fen Luo
- 作者服務機構: a Cellular and Molecular Pharmacology; Laboratory, Department of Pharmacology, and; b Department of Internal Medicine, Chang Gung College of Medicine and; Technology, Tao-Yuan, Taiwan, Republic of China
- 中文摘要: --
- 英文摘要: Regulation of the increases in inositol 1,4,5-trisphosphate (IP3) production and intracellular Ca2+ concentration ([Ca2+]i) by activation of protein kinase C (PKC) was investigated in cultured canine tracheal smooth muscle cells (TSMCs). Stimulation of TSMCs by carbachol led to IP3 formation and caused an initial transient peak of [Ca2+]i followed by a sustained elevation in a concentration-dependent manner. Pretreatment of TSMCs with phorbol 12- myristate 13-acetate (PMA, 1μM) for 30 min blocked the carbachol-induced IP3 formation and Ca2+ mobilization. Following preincubation, carbachol- induced Ca2+ mobilization recovered within 24 h. The concentrations of PMA that gave half-maximal inhibition of carbachol-induced IP3 formation and increase in [Ca2+]i were 7 and 4 nM, respectively. Prior treatment of TSMCs with staurosporine (1μM), a PKC inhibitor, inhibited the ability of PMA to attenuate carbachol-induced responses. Inactive phorbol ester, 4α-phorbol 12,13-didecanoate at 1μM , did not inhibit these responses to carbachol. The Kd and Bmax of the muscarinic receptor for [3H]N-methylscopolamine binding were not significantly changed by PMA treatment. PMA also decreased PKC activity in the cytosol of TSMCs, while increasing it transiently in the mem- branes within 30 min. Thereafter, the membrane-associated PKC activity decreased and persisted for at least 24 h of PMA treatment. Taken together, these results suggest that activation of PKC may inhibit phosphoinositide hydrolysis and consequently attenuate the [Ca2+]i increase or inhibit both responses independently. The inhibition by PMA of carbachol-induced re- sponses was inversely correlated with membranous PKC activity.
- 中文關鍵字: --
- 英文關鍵字: Phorbol ester; Carbachol; Protein kinase C; Inositol phosphates; Calcium ion; Muscarinic receptor; Tracheal smooth muscle cell