The P2Y purinoceptor-operated potassium channel is possibly regulated by the beta gamma subunits of a pertussis toxin-insensitive G-protein in cultured rat inferior colliculus neurons.
In whole-cell patches of inferior colliculus neurons, ADP evoked outwardly rectifying potassium currents with a latency of < 1 sec via P2Y purinoceptor. These currents were blocked by GDP beta S, while not by pertussis toxin (PTX). Additionally, a selective protein kinase C inhibitor, GF109203X, or a selective phospholipase A2 inhibitor, BPB, had no effect on the currents. In outside-out patches, ADP elicited single channel currents with same slope conductances as those obtained in cell-attached patches and the currents were again blocked by GDP beta S. The results presented here indicate that the P2Y purinoceptor-operated potassium channel in inferior colliculus neurons is activated only by a plasma membrane component, most likely by a direct coupling to the beta gamma subunits of a PTX-insensitive G-protein.
Ikeuchi
Y
Y
Department of Physiology, Kobe University School of Medicine, Japan.
Nishizaki
T
T
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004553:Electric Conductivity; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007245:Inferior Colliculi / Q000502:physiology*; D007700:Kinetics; D046911:Macromolecular Substances; D008301:Maleimides / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D037342:Pertussis Toxin; D015221:Potassium Channels / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D007211:Indoles; D046911:Macromolecular Substances; D008301:Maleimides; D015221:Potassium Channels; D018048:Receptors, Purinergic P2; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D006153:Guanosine Diphosphate; C023427:guanosine 5'-O-(2-thiodiphosphate); D000255:Adenosine Triphosphate; D037342:Pertussis Toxin; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; C070515:bisindolylmaleimide I