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. 1982 Dec;40(3):245–250. doi: 10.1016/S0006-3495(82)84479-2

Calcium-mediated decrease of a voltage-dependent potassium current.

D L Alkon, J J Shoukimas, E Heldman
PMCID: PMC1329000  PMID: 7183338

Abstract

Elevated intracellular Ca++ concentration reduces the amplitude of an early, voltage-dependent K+ current (IA) in the Type B photoreceptor of Hermissenda crassicornis. Internal Ca++ is increased by activating a voltage and light-dependent Ca++ current present in these cells or by direct iontophoresis of Ca++ ions. Substitution of Ba++ for Ca++ or elimination of Ca++ from the sea water bathing the cells abolishes the reduction in IA during paired light and depolarizing voltage steps. The delayed K+ current (IB) in these cells is also reduced during paired light and voltage steps, but this decrease of IB is not affected by removal of extracellular Ca++. IB (but not IA), apparently much less dependent on intracellular Ca++ levels, is reduced by light alone. Ca++ iontophoresis also abolishes the light-dependent Na+ current, which recovers with a time course of minutes.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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