A G protein couples serotonin and GABAB receptors to the same channels in hippocampus.
Both serotonin and the selective gamma-aminobutyric acidB (GABAB) agonist, baclofen, increase potassium (K+) conductance in hippocampal pyramidal cells. Although these agonists act on separate receptors, the potassium currents evoked by the agonists are not additive, indicating that the two receptors share the same potassium channels. Experiments with hydrolysis-resistant guanosine triphosphate (GTP) and guanosine diphosphate analogs and pertussis toxin indicate that the opening of the potassium channels by serotonin and GABAB receptors involves a pertussis toxin-sensitive GTP-binding (G) protein, which may directly couple the two receptors to the potassium channel.
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000494:pharmacology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects*; D007473:Ion Channels / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000378:metabolism; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology; D013134:Spiperone / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
D007473:Ion Channels; D010703:Phorbol Esters; D011963:Receptors, GABA-A; D011985:Receptors, Serotonin; D013873:Thionucleotides; D006153:Guanosine Diphosphate; D012701:Serotonin; D015240:Phorbol 12,13-Dibutyrate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D013134:Spiperone; C023427:guanosine 5'-O-(2-thiodiphosphate); D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D001418:Baclofen; D011188:Potassium; D002118:Calcium