Inhibition of voltage gated Ca2+ channels via Gbeta/gamma subunits

GABA B receptors are coupled to Gproteins and function by increasing the K+ and decreasing the Ca2+ inside the cell. The increase in K+ increases the negative membrane potential of the cell thereby hyper polarizing the cell which inhibits the release of neurotransmitters. The decrease in Ca2+ also inhibits neurotransmitter in two ways; first by preventing the fusion of synaptic vesicles containing the neurotransmitter with the plasma membrane and second by decreasing the Ca2+ dependent recruitment of synaptic vesicles to the plasma membrane. In particular GABA B receptors inhibit voltage gated Ca2+ channels via the activity of Gbeta/Ggamma subunits of G proteins.

γ-氨基丁酸B型受体与G蛋白相偶联，其功能通过增加细胞内的K+浓度和降低Ca2+浓度来实现。K+浓度的增加导致细胞膜负电位增强，从而超极化细胞，进而抑制神经递质的释放。Ca2+浓度的降低通过两种方式抑制神经递质的释放：首先，通过阻止含有神经递质的突触囊泡与质膜的融合；其次，通过降低依赖于Ca2+的突触囊泡向质膜的募集。特别是，GABA B受体通过G蛋白的Gbeta/Ggamma亚基的活性，抑制电压门控的Ca2+通道。