[Studies on the transmembrane signalling mechanism of the brain using Xenopus oocytes].
Xenopus oocytes have been used as an efficient and convenient expression system of messenger ribonucleic acid (mRNA) exogeneously injected. The transmembrane signalling mechanism of acetylcholine (ACh)- and serotonin (5-HT)-evoked inward current and properties of voltage-sensitive Ca channel (VSCC) current were studied using the oocytes injected with rat brain mRNA. M1 ACh or 5-HT1C receptor stimulation causes Cl- current via G-protein activation, inositol phosphate formation, an increase of free Ca2+ and finally gating of Cl channels via Ca2(+)-calmodulin. Protein kinase C seems to modulate the responses negatively. In addition, N type VSCC was also expressed and regulated by both protein kinases A and C. Limitations of the expression system as well as advantages are discussed.
Nomura
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Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
D000109:Acetylcholine / Q000502:physiology*; D000818:Animals; D001921:Brain; D015220:Calcium Channels / Q000378:metabolism*; D005071:Evoked Potentials; D009865:Oocytes / Q000378:metabolism*; D011494:Protein Kinases / Q000502:physiology; D012333:RNA, Messenger / Q000502:physiology*; D051381:Rats; D015290:Second Messenger Systems / Q000502:physiology; D012701:Serotonin / Q000502:physiology*; D014982:Xenopus laevis
D015220:Calcium Channels; D012333:RNA, Messenger; D012701:Serotonin; D011494:Protein Kinases; D000109:Acetylcholine