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Proc Biol Sci. 1994 Jan 22;255(1342):67-72.

pH-gated dopaminergic modulation of horizontal cell gap junctions in mammalian retina.

Author information

1
Department of Physiology and Pharmacology, University of Queensland, Brisbane, Australia.

Abstract

Horizontal cells mediate lateral inhibition in the outer retina, and this process is dependent on electrical coupling through gap junctions, giving rise to receptive fields that are much wider than the dendritic fields. This study on rabbit retina shows that the permeability of the gap junctions between A-type horizontal cells, as assessed by Lucifer yellow dye coupling, is modulated by dopamine through a D1 receptor linked to adenylate cyclase. Both exogenously applied dopamine and endogenously released dopamine uncoupled the horizontal cells, but the effect was pH-gated whereby it occurred only at an extracellular pH 7.2 +/- 0.05. The horizontal cells also uncoupled in acidic media (pH 7.0 or below) in the absence of dopamine. Our results show that horizontal cell coupling in the mammalian retina is regulated by both dopamine and pH. Given that the pH in the outer retina varies with the metabolic activity of the photoreceptors, these results suggest that ambient light conditions could gate the activity of neurotransmitters through pH-sensitive mechanisms.

PMID:
8153138
DOI:
10.1098/rspb.1994.0010
[Indexed for MEDLINE]

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