C protein (beta gamma) subunit-mediated presynaptic inhibition: regulation of exocytotic fusion downstream of Ca2+ entry.
The nervous system can modulate neurotransmitter release by neurotransmitter activation of heterotrimeric GTPDbinding protein (G protein)Dcoupled receptors. We found that microinjection of G protein bg subunits (Gbg) mimics serotoninOs inhibitory effect on neurotransmission. Release of free Gbg was critical for this effect because a Gbg scavenger blocked serotoninOs effect. Gbg had no effect on fast, action potentialDevoked intracellular Ca21 release that triggered neurotransmission. Inhibition of neurotransmitter release by serotonin was still seen after blockade of all classical Gbg effector pathways. Thus, Gbg blocked neurotransmitter release downstream of Ca21 entry and may directly target the exocytotic fusion machinery at the presynaptic terminal.
|Main Author:||Blackmer, Trillium.|
|Other Authors:||Larsen, Eric., Takahashi, Michiko., Martin, Thomas., Alford, Simon., Hamm, Heidi.|