Dihydropyridine-sensitive calcium currents in bipolar cells of salamander retina are inhibited by reductions in extracellular chloride

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Dihydropyridine-sensitive calcium currents (I(Ca)) in photoreceptors are unusual in that they can be inhibited by reductions in extracellular chloride. The present study examined whether I(Ca) in retinal bipolar cells, which as in photoreceptors mediates sustained neurotransmission, is also inhibited by reductions in chloride. Nystatin-perforated patch, whole cell recordings were obtained from bipolar cells in a retinal slice preparation of larval tiger salamander. In the presence of Ba2+, voltage steps above -40 mV evoked sustained inward currents, which were enhanced by the dihydropyridine, (-)BayK8644, and inhibited by nisoldipine. Similar to photoreceptors, replacing Cl- with gluconate or CH3SO4 inhibited bipolar cell I(Ca) and produced a negative shift in the current/voltage relationship. Thus, sensitivity to Cl- may be a more general property of L-type Ca2+ channel subtypes that mediate sustained neurotransmission. (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish (US)
Pages (from-to)155-158
Number of pages4
JournalNeuroscience Letters
Issue number3
Publication statusPublished - Feb 25 2000



  • Anion
  • Electrophysiology
  • Gluconate
  • L-type calcium current
  • Ribbon synapse
  • Sustained neurotransmission

ASJC Scopus subject areas

  • Neuroscience(all)

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