Figure 13.
Schematic of local circuit underlying GABABR-mediated regulation of bursts in the SC. Postsynaptic GABABRs expressed both in NFV and WFV cells and presynaptic GABABRs located on glutamatergic synaptic terminals in the SGS are activated by synaptically released GABA during bursts of SGS GABAergic neurons. Hyperpolarization in NFV cells, shunting inhibition in WFV cells, and reduction of glutamate release may contribute to the limitation of burst duration. When GABABRs are blocked, burst duration in the SGS may be prolonged in an NMDAR-dependent manner, and then, the prolonged burst may spread to the SGI. Thus the burst duration of the SGI may also be prolonged. Note that the localization of the receptors and synaptic connections essential to explain the present results are depicted, and other components, such as AMPA/kainate receptors and GABAARs, are not drawn for clarity.