Mapping synaptic inputs to kisspeptin neurons using a conditional transneuronal viral tracer
Kisspeptin neuropeptides, encoded by the Kiss1 gene, are key regulators of the mammalian reproductive axis by potently stimulating GnRH release. Kiss1 neurons are located in two main areas of the hypothalamus: the AVPV region, which controls the preovulatory LH surge and the ARC region, which controls basal GnRH pulsatility. One of the fundamental steps in understanding how the reproductive axis is co-ordinated with other physiological processes is an accurate description of the neuronal circuitry communicating with Kiss1 neurons. We have generated a transgenic mouse line that expresses the CRE recombinase specifically in Kiss1 neurons. We have used this mouse line to undertake conditional viral tracing with a genetically modified pseudorabies virus (Ba2001) to define afferent neuronal inputs to Kiss1 neurons. Several of these neuronal populations have been implicated as physiologically relevant in controlling the reproductive axis. These include the suprachiasmatic nucleus, which communicates information about day length; the subfornical organ, which provides information about peripheral metabolic status; the amygdala, which responds to pheromone signals and POMC and NPY neurons in the ARC, which regulate feeding behaviour. We are currently studying these connections to define their functional relevance in regulating Kiss1 neuronal activity. FINANCIAL SUPPORT: This work was funded by a BBSRC grant (BB/K003178/1).