title: Consequences of transient retinal hypoxia on rod input to horizontal cells in the rat retina.
abstract: The effects of hypoxia on horizontal cells were studied by intracellular recording in the superfused rat retina. Hypoxic challenge from the photoreceptor surface resulted in horizontal cell depolarization, associated with a reduction of the light-evoked hyperpolarization (S-potential). This depolarization, though not the reduction in S-potential, was reversed by non-NMDA receptor antagonists, but not by NMDA related antagonists. Horizontal cells were also depolarized during hypoxia when calcium-dependent synaptic transmitter release was blocked by Co2+. Diazoxide, an activator of ATP-sensitive K+ channels (K+ATP), had no effect on normal cells but blocked the depolarization and the reduction in S-potential. We conclude that retinal hypoxia results in increased activation of the non-NMDA receptors of horizontal cells, whilst the activation of K+ATP channels may be protective in retinal hypoxia.
authors.affiliation: Vision Research Unit (UMDS), Rayne Institute, St Thomas' Hospital, London, England.
authors.forename: M W
authors.initials: MW
authors.lastname: Hankins
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000502:physiology; D046508:Culture Techniques; D003981:Diazoxide / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D007395:Interneurons / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D010786:Photoreceptor Cells / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D005971:Glutamates; D018698:Glutamic Acid; D003981:Diazoxide