We have shown before that the duration and amplitude of both prolonged (1-160 s) and short (100-1000 ms) depolarizing prepulse altered all the steady-state and kinetic parameters of rNa(v)1.2a voltage-gated sodium channel in a pseudo-oscillatory fashion with variable time period and amplitude, often superimposed on a linear trend. In this study, we have examined the effect of G-protein activation on pseudo-oscillatory properties of the rNa(v)1.2a sodium channel alpha subunit, heterologously expressed in Chinese hamster ovary cells. G-protein modification caused insignificant changes in the slow pseudo-periodic oscillation of the activation properties of sodium channel; only the time period of the oscillation was altered from similar to 30 to 21 s. In contrast, G-protein activation abolished the faster component of pseudo-periodic oscillation in steady-state inactivation properties of sodium channel; the conditioning duration dependence of steady-state inactivation becomes monotonic in nature. (c) 2006 Elsevier Inc. All rights reserved.