Maturation of a transient outward potassium current in mouse fetal hypothalamic neurons in culture

Sikdar, SK and Legendre, P and Dupouy, B and Vincent, JD (1991) Maturation of a transient outward potassium current in mouse fetal hypothalamic neurons in culture. In: Neuroscience, 43 (2-3). pp. 503-511.

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Abstract

The whole-cell voltage clamp technique was used to record potassium currents in mouse fetal hypothalamic neurons developing in culture medium from days 1 to 17. The neurons were derived from fetuses of IOPS/OF1 mice on the 14th day of gestation. The mature neurons (>six days in culture) showed both a transient potassium current and a non-inactivating delayed rectifier potassium current. These were identified pharmacologically by using the potassium channel blockers tetraethyl ammonium chloride and 4-aminopyridine, and on the basis of their kinetics and voltage sensitivities. The delayed rectifier potassium current had a threshold of −20 mV, a slow time-course of activation, and was sustained during the voltage pulse. The 4-aminopyridine-sensitive current was transient, and was activated from a holding potential more negative (−80 mV) than that required for evoking the delayed rectifier potassium current (−40 mV). The delayed rectifier potassium current was detectable from day 1 onwards, while the transient potassium current showed a distinct developmental trend. The time-constant of inactivation became faster with age in culture. The half steady-state inactivation potential showed a shift towards less negative membrane potentials with age, and the relationship was best described by a logarithmic regression equation.The developmental trend of the transient potassium current may relate functionally to the progressive morphological changes, and the appearance of synaptic connections during ontogenesis.

Item Type:	Journal Article
Publication:	Neuroscience
Publisher:	Elsevier science
Additional Information:	Copyright of this article belongs to Elsevier science.
Keywords:	Muscle-Cells;Calcium;Conductance;Drosophila;Responses; Channels;Nucleus;4-Aminopyridine;Modulation;Aplysia.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	23 Nov 2010 10:04
Last Modified:	23 Nov 2010 10:04
URI:	http://eprints.iisc.ac.in/id/eprint/33960

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