Figure 10. Photoactivation of Kiss1^ARH fibers excites Kiss1^AVPV/PeN neurons via glutamate release.

(A) Schematic drawing of a coronal section showing the bilateral viral injections in the ARH with AAV-DIO-ChR2:mCherry. (B) Sagittal brain slice (B1) and confocal images from the slice (B2, 3) of mouse bilaterally injected with a ChR2-mCherry-expressing viral vector into the ARH of Kiss1-Cre::GnRH-EGFP female mouse. Projections from Kiss1^ARH neurons (B3) to the AVPV/PeN are illustrated (B2). Green neurons in the POA illustrate the location of GnRH neurons in the sagittal brain slice. Scale bars, 100 µm (B2, B3). (C) Overlay of epifluorescence (YFP) and differential interference contrast (DIC) images of a coronal arcuate slice showing injection site (C1) in a Kiss1-Cre:ChR2:YFP mouse (arrow points to high power image of labeled neurons in the ARH) and fiber-projections to the AVPV (C2; arrow points to labeled fibers in the AVPV area that are being photostimulated). Scale bars = 10 µm. (D) Example of light-evoked fast EPSCs in a Kiss1^AVPV/PeN neuron (mean response: 33.2 ± 9.7 pA, n = 5). Red trace indicates averaged sweeps. Blue trace illustrates that the AMPA- and NMDA-mediated currents (EPSCs) were blocked with CNQX (10 μM) and D-AP5 (50 μM). Following recording, cells were harvested for scRT-PCR determination of Kiss1 mRNA expression. All recorded AVPV/PeN cells (n = 5) expressed Kiss1 mRNA (data not shown). ARH, hypothalamic arcuate nucleus; AVPV/PeN, anteroventral periventricular and periventricular preoptic nuclei; POA, preoptic area.

DOI: http://dx.doi.org/10.7554/eLife.16246.012