Metabotropic responses to acetylcholine and serotonin of Xenopus oocytes injected with rat brain mRNA are transduced by different G-protein subtypes.
To assign the GTP-binding protein (G-protein) subtype involved in the signal transduction from exogenous receptors to phospholipase C in the Xenopus oocyte translation system, antisense DNA complementary to rat G-protein alpha-subunit mRNA was designed and injected together with rat brain poly(A)+ RNA. Current response of mRNA-injected oocytes to acetylcholine (ACh) was suppressed dose-dependently by a co-injection of Gil alpha-antisense DNA, but response of the same oocytes to serotonin (5-HT) was not inhibited. In the oocytes co-injected with Go alpha-antisense DNA, the 5-HT response was more effectively suppressed than the ACh response. These results suggest that Go alpha but not Gil alpha intermediates brain 5-HT1C receptor function, and in contrast, muscarinic receptors derived from rat brain utilize Gil alpha rather than Go alpha to activate phospholipase C.
Kaneko
S
S
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Takahashi
H
H
Satoh
M
M
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001345:Autoradiography; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D016373:DNA, Antisense / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008845:Microinjections; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D012701:Serotonin / Q000378:metabolism*; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000378:metabolism; D014981:Xenopus
D016373:DNA, Antisense; D012333:RNA, Messenger; D012701:Serotonin; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D000109:Acetylcholine