VOLTAGE-GATED NA-T3-1 PITUITARY GONADOTROPH CELLS( CHANNELS CONTRIBUTE TO MEMBRANE VOLTAGE FLUCTUATION IN ALPHA)

alpha T3-1 cells showed a slope resistance of 1.8 G Omega. The cell me mbrane surface was not smooth and a scanning electron micrograph showe d a complex structure with blebs and microvilli like projections. The cells showed spontaneous fluctuations at zero current resting membrane potential and hyperpolarization increased the amplitude of membrane p otential fluctuations. The amplitude of membrane potential fluctuation s at hyperpolarized membrane potential was attenuated on application o f TTX to the bath solution. The potential at which half steady state i nactivation of isolated sodium current occurred, was at a very hyperpo larized potential (-95.4 mV). The study presented in this paper shows that the voltage gated sodium channels contribute to the increase in t he amplitude of electrical noise with hyperpolarization in alpha T3-1 cells. (C) 1998 Published by Elsevier Science Ireland Ltd.