| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
A GABA_B specific monoclonal antibody directly inhibited [^3H] GABA binding to GABA_B receptor in bovine cerebral synaptic membrane. Long preincubation time and excess amount of the antibody were apparently needed for inducing inhibition, however, only one molecule of antibody could block one receptor molecule. The binding activity of solubilized GABA_B receptor disappeared after the absorption on immunobeads, prepared by the conjugation of cyanogen bromide-activated agarose beads and the monoclonal antibody. On the other hand, presence of excess amount of GABA did not affect on the receptor-antibody interaction.
The antibody, not only inhibited the GABA binding to the receptor, but also interrupted the signal transduction from the GABA_B receptor to adenylyl cyclase in cerebral synaptic membrane. Agonists for GABA_B receptor usually inhibited the adenyly cyclase via inhibitory G protein (Gi, o). Preincubation of synaptic membrane with the monoclonal antibody canceled this inhibition. These results, taken together, indicated that the monoclonal antibody acts as antagonist for the GABA_B receptor. Because the affinity between the receptor and the monoclonal antibody was much more stronger than that of GABA,the native neurotransmitter, this antibody might be useful for the analysis of GABA_B receptor function in the brain.
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