Figure 5.

Ventral periaqueductal gray/dorsal raphe (vPAG/DR) tyrosine hydroxylase (TH) neurons release dopamine and glutamate in the bed nucleus of the stria terminalis (BNST). In a TH-cre mouse line, a cre-inducible channelrhodopsin viral construct was injected into the vPAG/DR. (a) Confocal image demonstrates the high-degree of colocalization of channelrhodopsin enhanced yellow fluorescent protein (green), and TH staining mCherry (red) in the injection site. (b) In the vPAG/DR, blue light presentation induced light-evoked action potentials in TH cell bodies expressing channelrhodopsin. In the BNST, channelrhodopsin-mediated light activation of vPAG/DR TH terminals evoked both GABAergic (c) and glutamatergic (d) currents in the post-synaptic BNST neurons, with GABAergic current displaying a significantly increased latency to current onset (e). (f) Using fast-scan cyclic voltammetry (FSCV), dopamine release from the vPAG/DR TH terminals was detected in the BNST at different optogenetic stimulation parameters. (g) Cyclic voltammogram of dopamine release. (h) FSCV color plot representing dopamine release.