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Absence of detubulation in frog twitch muscle fibres exposed to protein kinase c activator

Zhang Xiaohui, Zhu Peihong

Shanghai Institute of Physiology,Chinese Academy of Sciences. Shanghai 200031,China

Abstract

It has been shown that excitation-contraction(e-c) uncoupling occurred in frog twitch muscle fibres exposed to phorbol 12, 13-dibutyrate (PDBu), a protein dinase C activator. To investigae if this uncoupling results from detubtilation of the transverse tubules, intracellularly evoked action potentials were examined.The after-depolarization of the action potential, representing intact transverse tubules was gradally abolished by osmotic detubulation, while those obtained from the fibres incubated in 1 #mu#mol/L PDBu for 12 or 24 h still possessed the after-depodrization. Thus, it showed that the transverse tubdes were shll intact in frog twitch muscle fibres after exposure to PDBu. The mechedsm of e-c uncoupling induced by PDBu remains to be clarified.

Key words: After-depolarization;Transverse tubule;Detubalation;Excitation-contraction coupling

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Citing This Article：

Zhang Xiaohui, Zhu Peihong. Absence of detubulation in frog twitch muscle fibres exposed to protein kinase c activator. Acta Physiol Sin 1998; 50 (2): (in Chinese with English abstract).