Identification of galpha subtype(s) involved in gamma-aminobutyric acid(B) receptor-mediated high-affinity guanosine triphosphatase activity in rat cerebral cortical membranes.
The ability of a series of specific Galpha carboxyl-terminal antisera, (i.e. anti-Gsalpha, anti-Gi1/2alpha, anti-Gi3alpha/Goalpha, anti-Goalpha/Gi3alpha, and anti-Gq/11alpha) to disrupt (+/-)-baclofen-stimulated high-affinity guanosine triphosphatase (GTPase) activity was explored in rat cerebral cortical membranes to identify the Galpha subunit(s) involved in gamma-aminobutyric acid(B) (GABA(B)) receptor-mediated signal transduction. Pretreatment of the membranes with the AS/7 (anti-Gi1/2alpha) antiserum inhibited GABA(B) receptor-mediated response without affecting the basal activity. The RM/1 (anti-Gsalpha) and QL (anti-Gq/11alpha) antisera failed to inhibit GABA(B) receptor-coupled responses. The results of the EC/2 (anti-Gi3alpha/Goalpha) and GO/1 (anti-Goalpha/Gi3alpha) antisera were difficult to interpret since the basal activities were influenced by these antisera. These results, in conjunction with the data in our previous reconstitution study, indicate that Gi2alpha is a main transducer of GABA(B) receptor-mediated signaling in rat cerebral cortex.
Odagaki
Y
Y
Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, 060-8638, Sapporo, Japan. odagaki@saitama-med.ac.jp
Koyama
T
T
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001418:Baclofen / Q000494:pharmacology; D001798:Blood Proteins / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002540:Cerebral Cortex / Q000378:metabolism*; D018755:GABA Agonists / Q000494:pharmacology; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000276:immunology / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D008297:Male; D011518:Proto-Oncogene Proteins / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018080:Receptors, GABA-B / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D000906:Antibodies; D001798:Blood Proteins; D018755:GABA Agonists; D011518:Proto-Oncogene Proteins; D018080:Receptors, GABA-B; D006160:Guanosine Triphosphate; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; C498017:Gnai2 protein, rat; D001418:Baclofen