The kinetics of a non-inactivating $K^+$ current in $\alpha T3-1$ pituitary gonadotropes is not affected by holding potential

Tiwari, JK and Sikdar, SK (2000) The kinetics of a non-inactivating $K^+$ current in $\alpha T3-1$ pituitary gonadotropes is not affected by holding potential. In: Brain Research, 873 (2). pp. 218-224.

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Abstract

The non-inactivating $K^+$ currents in $\alpha T3-1$, 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, $V_{HOLD}=−80 \hspace{2mm} mV$ in presence of 4-AP (4-aminopyridine), and $V_{HOLD}=−10 \hspace{2mm} mV$ 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.

Item Type:	Journal Article
Publication:	Brain Research
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Cole–Moore delay;Voltage gated K+ channels;Patch-clamp;αT3-1 gonadotrope
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	08 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12121

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