ZFIN ID: ZDB-PUB-051012-6
Dopamine modulates voltage-activated potassium currents in zebrafish retinal on bipolar cells
Yu, C.J., and Li, L.
Date: 2005
Source: Journal of neuroscience research   82(3): 368-376 (Journal)
Registered Authors: Li, Lei
Keywords: potassium current, dopamine, retinal bipolar cell, zebrafish
MeSH Terms:
  • 8-Bromo Cyclic Adenosine Monophosphate/pharmacology
  • Animals
  • Cells, Cultured
  • Cyclic AMP/metabolism
  • Dopamine/metabolism*
  • Dopamine/pharmacology
  • Dopamine Agonists/pharmacology
  • Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology
  • Membrane Potentials/drug effects
  • Membrane Potentials/physiology
  • Patch-Clamp Techniques
  • Potassium Channels, Voltage-Gated/drug effects
  • Potassium Channels, Voltage-Gated/metabolism*
  • Reaction Time/drug effects
  • Reaction Time/physiology
  • Receptors, Dopamine D1/agonists
  • Receptors, Dopamine D1/metabolism*
  • Receptors, G-Protein-Coupled/agonists
  • Receptors, G-Protein-Coupled/metabolism*
  • Retina/drug effects
  • Retina/metabolism*
  • Retinal Bipolar Cells/drug effects
  • Retinal Bipolar Cells/metabolism*
  • Zebrafish
PubMed: 16206280 Full text @ J. Neurosci. Res.
We report a study of the characterization of voltage-activated potassium (K(+)) currents in retinal ON bipolar cells in zebrafish. At single-channels levels, the open probability of the K(+) channels increased when the membrane potential was increased. The maximal open proportion was 0.76 +/- 0.05 under our testing conditions. In whole-cell recordings, the K(+) current displayed two exponential components with the activation time constants of 11-22 msec (tau1) and 0.8-4 msec (tau2). Dopamine modulated the K(+) current. Dopamine reduced the time constant tau2 when the membrane potential was depolarized to high voltages. A decrease in K(+) current was seen when dopamine D(1) receptors were selectively activated by SKF38393 or when the D(1) receptor-coupled G-proteins were activated by GTP-gamma-S. The activation of adenylate cyclase by forskolin or the increase of intracellular cAMP concentrations by 8-Br-cAMP or Sp-cAMPS also resulted in a decrease in K(+) current. Together, the data suggest that dopamine modulates the K(+) current via D(1) receptor-coupled G-protein pathways.