Table 1.

Coupling of G protein subunits with effectors and the cellular consequences of such interactions.

G protein subunit	Target	Cellular Effect	Effect on Neurotransmission	References
Gαi/o	Adenylyl cyclase	Inhibition, reduction in cAMP	Inhibition of neurotransmitter release	[26, 108]
Gβγ	VDCC inhibition	Reduced ICa	Reduced neurotransmitter release	[109, 110]
Gβγ	K channel activation	Increased IK, reduced cellular excitability	Reduced neurotransmitter release	[111–113]
Gβγ	Vesicular release machinery	Inhibition of vesicular release	Inhibition of neurotransmitter release	[114–116]
Gβγ	PLCβ	PKC activation, increase intracellular Ca2+	Inhibition of neurotransmitter release	[117]
Gβγ	Adenylyl cyclase	Activation or inhibition, increase or decrease in cAMP	Inhibition or enhancement of neurotransmitter release1	[26, 108]
Gβγ	Kinases: MAPK, βARK, PI3K	Phosphorylation of target proteins	Inhibition or enhancement of neurotransmitter release1	[118–120]

¹G_βγ-mediated effects on presynaptic-modulation neurotransmission for the indicated effectors remain to be directly demonstrated.