PUBLICATION
Differential expression of voltage-gated K+ and Ca2+ currents in bipolar cells in the zebrafish retinal slice
- Authors
- Connaughton, V.P. and Maguire, G.
- ID
- ZDB-PUB-980514-11
- Date
- 1998
- Source
- The European journal of neuroscience 10: 1350-1362 (Journal)
- Registered Authors
- Connaughton, Victoria P.
- Keywords
- bipolar cells; Danio rerio; electrophysiology; retina; zebrafish
- MeSH Terms
-
- Animals
- Calcium Channel Blockers/pharmacology
- Calcium Channels/physiology*
- In Vitro Techniques
- Ion Channel Gating*
- Membrane Potentials/physiology
- Neurons/physiology*
- Potassium Channel Blockers
- Potassium Channels/physiology*
- Retina/cytology
- Retina/physiology*
- Zebrafish
- PubMed
- 9749789 Full text @ Eur. J. Neurosci.
Citation
Connaughton, V.P. and Maguire, G. (1998) Differential expression of voltage-gated K+ and Ca2+ currents in bipolar cells in the zebrafish retinal slice. The European journal of neuroscience. 10:1350-1362.
Abstract
Whole-cell voltage-gated currents were recorded from bipolar cells in the zebrafish retinal slice. Two physiological populations of bipolar cells were identified. In the first, depolarizing voltage steps elicited a rapidly activating A-current that reached peak amplitude < or = 5 ms of step onset. IA was antagonized by external tetraethylammonium or 4-aminopyridine, and by intracellular caesium. The second population expressed a delayed rectifying potassium current (IK) that reached peak amplitude > or = 10 ms after step onset and did not inactivate. IK was antagonized by internal caesium and external tetraethylammonium. Bipolar cells expressing IK also expressed a time-dependent h-current at membrane potentials < -50 mV. Ih was sensitive to external caesium and barium, and was also reduced by Na+-free Ringer. In both groups, a calcium current (ICa) and a calcium-dependent potassium current (IK(Ca)) were identified. Depolarizing voltage steps > -50 mV activated ICa, which reached peak amplitude between -20 and -10 mV. ICa was eliminated in Ca+2-free Ringer and blocked by cadmium and cobalt, but not tetrodotoxin. In most cells, Ica was transient, activating rapidly at -50 mV. This current was antagonized by nickel. The remaining bipolar cells expressed a nifedipine-sensitive sustained current that activated between -40 and -30 mV, with both slower kinetics and smaller amplitude than transient ICa. IK(Ca) was elicited by membrane depolarizations > -20 mV. Bipolar cells in the zebrafish retinal slice preparation express an array of voltage-gated currents which contribute to non-linear I-V characteristics. The zebrafish retinal slice preparation is well-suited to patch clamp analyses of membrane mechanisms and provides a suitable model for studying genetic defects in visual system development.
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Human Disease / Model
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