Evidence for Inhibitory Effects of Flupirtine, a Centrally Acting Analgesic, on Delayed Rectifier K+ Currents in Motor Neuron-Like Cells
Figure 2
Evaluation of the kinetics of Flu-induced block of in NSC-34 neuronal cells. In (A), the time courses of current inactivation obtained in the absence (a) and presence of 1 M (b) and 3 M (c) Flu were well fitted by a single exponential shown in (B). Inset in (A) indicates the voltage protocol used. In (C), the kinetics of Flu-induced block of in NSC-34 cells was evaluated. The reciprocal of inactivation time constant of () obtained by exponential fit to the trajectory of decay was plotted against the Flu concentration. Data points were fitted by a linear regression shown in blue line, indicating that Flu-induced blocking occurs with a molecularity of 1. Blocking () and unblocking () rate constants, given by the slope and the -axis intercept of the interpolated line, were 0.0564 sec−1 M−1 and 0.504 sec−1, respectively. (D) Summary of the data showing the effect of Flu and linopirdine (Lino; 10 M) on the inactivation time constants () of elicited by a 10-sec depolarizing pulse from −50 to +50 mV (mean ± SEM; –10 for each point). In the experiments with Flu plus linopirdine, linopirdine (10 M) was applied after the addition of Flu (3 M). *Significantly different from control.
