Dantrolene-Induced Inhibition of Skeletal L-Type Ca2+ Current Requires RyR1 Expression
Figure 5
Skeletal L-type Ca2+ currents are little affected by Dantrolene in the absence of RyR1. Representative current families evoked from −80 mV to 0, 10, 20, 30, and 40 mV for dyspedic myotubes treated with DMSO vehicle (a) or 10 M Dantrolene (b) for >10 minutes at ~25°C. In the case of the latter, the step from −80 mV to 0 mV evoked some T-type current visible at the beginning of the pulse. Peak - relationships are shown in (c). Smooth - curves were fit by (1) (see “Section 2”) with the following respective parameters for control () and Dantrolene-treated () groups: and nS/nF; and mV; and mV. No significant (, unpaired t-test) differences were observed amongst the fit parameters. (d) Comparison of conductance-voltage relationships for control and Dantrolene-treated dyspedic myotubes. The average conductance values (derived from - data using (2); see Section 2). (e) Inactivation summary. = fraction of the peak current remaining at the end of the 200 ms test depolarization to +30 mV.
