GABA_B receptor modulation of synaptic function

Neuromodulators have complex effects on both the presynaptic release and postsynaptic detection of neurotransmitters. Here we describe recent advances in our understanding of synaptic modulation by metabotropic GABA_B receptors. By inhibiting multivesicular release from the presynaptic terminal, these receptors decrease the synaptic glutamate signal. GABA_B receptors also inhibit the Ca²⁺ permeability of NMDA receptors to decrease Ca²⁺ signals in postsynaptic spines. These new findings highlight the importance of GABA_B receptors in regulating many aspects of synaptic transmission. They also point to novel questions about the spatiotemporal dynamics and sources of synaptic modulation in the brain.