Kisspeptins and their receptors are potent regulators of the gonadotropic axis.
Kisspeptin neurons are found mainly in the hypothalamic arcuate nucleus and the
anteroventral periventricular nucleus. However, there is also a third population of
kisspeptin neurons located in the amygdala.
We used fluorescence immunohistochemistry to quantify and localize the amygdala
kisspeptin neurons and to reveal close apposition and putative innervations by
vasopressinergic and tyrosine hydroxylase positive dopaminergic neurons. Using
microinjections of retro- and anterograde tracers, and viral transfection systems in rats
and transgenic mice, we showed reciprocal connectivity between the accessory
olfactory bulb and the amygdala kisspeptin neurons. In vitro recordings indicate an
inhibitory action of kisspeptin on mitral cells in the accessory olfactory bulb. Using
viral specific-cell gene expression in transgenic mice in combination with double
immunofluorescence histochemistry we found that the amygdala kisspeptin neurons
also project to gonadotropin-releasing hormone (GnRH) neurons in the preoptic area.
Our neuroanatomical and electrophysiological data suggest that amygdala kisspeptin
neurons integrate social behaviour and odour information to GnRH neurons in the
preoptic area to coordinate the gonadotropic axis and the appropriate output behaviour
to odour cues.