Voltage-gated potassium channels in retinal ganglion cells of trout: a combined biophysical, pharmacological, and single-cell RT-PCR approach.
Retinal ganglion cells of young mature trout were acutely isolated by tissue printing and analyzed with the whole-cell mode of the patch-clamp technique in combination with single-cell RT-PCR. All cells either exhibited spontaneous spiking activity or could be induced to fire trains of action potentials by current injection. Depolarizing voltage steps elicited a TTX-sensitive sodium inward current and a complex outward current that could be subdivided into a calcium-dependent component that was sensitive to 100 nM iberiotoxin as well as three major types of voltage-sensitive currents: 1) a high-threshold (-20 mV) noninactivating current that was highly sensitive to submicromolar TEA and quinine, resembling recombinant mammalian Kv3.1 channels; 2) a low-threshold DTX-sensitive current, matching mammalian Kv1; and 3) a fast-inactivating transient current that was highly sensitive to TEA (3 mM) but resistant to alpha-DTX (1 microM) and quinine (0.1 mM). By multiplex single-cell RT-PCR, coexpression of multiple transcripts encoding Shaker-related channel genes of trout (termed Tsha1-Tsha4) as well as two Shaw-related channels (termed Traw1 and Traw2) could be demonstrated in individual cells.
Henne
J
J
Abteilung Zoophysiologie, Universität Osnabrück, Osnabrück, Germany.
Pöttering
S
S
Jeserich
G
G
D000200:Action Potentials; D000818:Animals; D004546:Elapid Venoms / Q000494:pharmacology; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D024642:Potassium Channels, Voltage-Gated; D011803:Quinine / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051637:Shaker Superfamily of Potassium Channels; D051670:Shaw Potassium Channels; D015222:Sodium Channels / Q000502:physiology; D019789:Tetraethylammonium / Q000494:pharmacology; D014337:Trout
D004546:Elapid Venoms; D009479:Neuropeptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger; D051637:Shaker Superfamily of Potassium Channels; D051670:Shaw Potassium Channels; D015222:Sodium Channels; D019789:Tetraethylammonium; C020273:dendrotoxin; D011803:Quinine