[Analysis of receptor-ion channel functions in Xenopus oocyte translation system].
Xenopus oocytes has been utilized to analyze the intracellular signaling and coupling mechanisms between neurotransmitter receptors and ion channels. (1) The GTP-binding protein-coupled intracellular signaling pathway was analyzed in oocytes expressing metabotropic receptors by brain mRNA. These metabotropic receptors are commonly linked to the sequence of phosphoinositide metabolism, intracellular Ca2+ increase and opening of Ca(2+)-dependent Cl- channels. An antisense DNA study indicated that a specific subtype of GTP-binding protein is involved in the coupling of each metabotropic receptor. (2) Effects of central acting drugs on the functions of glutamate receptor subtypes and voltage-dependent Ca2+ channels were evaluated, and the data were compared with the results from conventional in vitro assays using brain preparations. (3) A series of experiments on kappa-opioid receptors indicated that kappa-opioid receptors can couple with multiple signaling systems in the oocytes via GTP-binding proteins Gi/G(o), which involves mobilization of intracellular Ca2+ through phosphoinositide metabolism, synergistic potentiation of cyclic AMP production, and inhibition of voltage-dependent Ca2+ channels.
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
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Kaneko
D000818:Animals; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D009865:Oocytes; D010716:Phosphatidylinositols / Q000378:metabolism; D011485:Protein Binding; D017981:Receptors, Neurotransmitter / Q000378:metabolism; D011957:Receptors, Opioid / Q000378:metabolism; D015398:Signal Transduction; D014982:Xenopus laevis
D007473:Ion Channels; D010716:Phosphatidylinositols; D017981:Receptors, Neurotransmitter; D011957:Receptors, Opioid; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D002118:Calcium