[Absence of detubulation in frog twitch muscle fibres exposed to protein kinase C activator].
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 kinase C activator. To investigate if this uncoupling results from detubulation of the transverse tubules, intracellularly evoked action potentials were examined. The after-depolarization of the action potential, representing intact transverse tubules was gradually abolished by osmotic detubulation, while those obtained from the fibres incubated in 1 mumol/L PDBu for 12 or 24 h still possessed the after-depolarization. Thus, it showed that the transverse tubules were still intact in frog twitch muscle fibres after exposure to PDBu. The mechanism of e-c uncoupling induced by PDBu remains to be clarified.
Zhang
X H
XH
Shanghai Institute of Physiology, Chinese Academy of Sciences, Shanghai 200031.
Zhu
P H
PH
D000200:Action Potentials; D000818:Animals; D020536:Enzyme Activators / Q000494:pharmacology; D009119:Muscle Contraction; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D011493:Protein Kinase C; D011898:Ranidae
D020536:Enzyme Activators; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C