Voltage-dependent gating of veratridine-modified RIIA Na+ channel alpha subunit expressed heterologously in CHO cells.
The voltage-dependent kinetics of veratridine-modified RIIA Na+ channel alpha subunit expressed heterologously in CHO cells were studied using the whole-cell patch-clamp technique. The activation and deactivation kinetics are well described by double exponential functions but poorly by a monoexponential function. Unlike the slow component, the fast time constant and associated amplitude factor depended steeply on the potential. The steady-state activation of veratridine-modified channels is described by a Boltzmann function with a V1/2 of -131.9 mV and a slope of 9.41 mV. A two-state model is proposed for the fast component that explains the kinetics of veratridine's mechanism of action.
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India.
A S
AS
Ghatpande
S K
SK
Sikdar
D000818:Animals; D016466:CHO Cells / Q000378:metabolism*; D006224:Cricetinae; D004553:Electric Conductivity; D015870:Gene Expression; D015640:Ion Channel Gating / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D015222:Sodium Channels / Q000235:genetics* / Q000502:physiology*; D014701:Veratridine / Q000494:pharmacology*
D015222:Sodium Channels; D014701:Veratridine