| 10930547 |
Tiwari JK, Sikdar SK: The kinetics of a non-inactivating K (+) current in alphaT3-1 pituitary gonadotropes is not affected by holding potential. Brain Res. 2000 Aug 11;873(2):218-24.
The non-inactivating K (+) currents in alphaT3-1, a gonadotroph cell line, were recorded in the presence of low intracellular free calcium concentration. The activation kinetics of the whole-cell currents and the gating charge measured from holding potential (V (HOLD)) of -10 mV, V (HOLD)=-80 mV in presence of 4-AP (4-aminopyridine), and V (HOLD)=-10 mV with a hyperpolarizing prepulse to -80 mV were similar. No difference was observed in the onset of currents elicited from the hyperpolarizing potentials, suggesting deviation from the Cole-Moore prediction of increase in the delay of current onset with increasing hyperpolarization. The data suggests that the channel opens with at least one rate-limiting voltage-dependent step, which may imply that the position of the voltage sensor is unaffected by hyperpolarization. |
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