Leptin Responsive and GABAergic Projections to the Rostral Preoptic Area in XXXX .

@entity18070 @entity1246 @entity19 @entity2339 @entity1176 @entity22844
UNASSIGNED: The adipocyte derived hormone leptin plays a critical role in the control of reproduction via signalling in hypothalamic neurones. The drivers of the @entity2339 , the @entity1176 neurones, do not have the receptors for leptin. Therefore, intermediate leptin responsive neurones must provide leptin-to- @entity1176 signalling. We investigated the populations of leptin responsive neurones that provide input to the rostral preoptic area (rPOA, where @entity1176 cell bodies reside). Fluorescent retrograde tracer beads (RetroBeads) were injected into the rPOA of transgenic leptin receptor reporter ( @entity18070 -eGFP) female @entity19 . Uptake of the RetroBeads by @entity18070 -eGFP neurones was assessed throughout the hypothalamus. RetroBead uptake was most evident in the medial arcuate nucleus (Arc), the dorsomedial nucleus (DMN), and the ventral premammillary nucleus ( @entity22844 ) of the hypothalamus. The uptake of RetroBeads specifically by @entity18070 -eGFP neurones was highest in the medial Arc (18% of tracer-labelled neurons @entity18070 -eGFP-positive). Since we have previously shown that neurones which are both leptin responsive and GABAergic play a critical role in leptin's regulation of fertility, we next focussed on the location of these populations. To address whether GABAergic neurones in leptin-responsive hypothalamic regions project to the rPOA, the experiment was repeated in @entity1246 neurone reporter @entity19 (Vgat-tdTomato). Between 10 and 45% of RetroBead labelled neurones in the Arc were GABAergic, whereas uptake of tracer by GABAergic neurones in the DMN and @entity22844 was very low (<5%). These results show that both leptin responsive and GABAergic neurones from the Arc project to the region of the @entity1176 cell bodies. Our findings suggest that @entity18070 -expressing @entity1246 neurones from the Arc may be mediators of leptin-to- @entity1176 signalling. This article is protected by copyright. All rights reserved.
