Reproduction is an intricate process that involves countless hormones and neuropeptides, and is modulated in its various steps by the hypothalamic-pituitary-gonadal (HPG) axis. The HPG axis is controlled majorly by gonadotropin releasing hormone (GnRH) neurons, that are mainly influenced by kisspeptin and gamma-aminobutyric acid (GABA), which are secreted by neurons of the central nervous system. Such influence is known, but the relation between these two elements and how it affects the estrous cycle remains an open question. This subject can be investigated through coexpression analysis of the Kiss1 gene (expressed in kisspeptin producing neurons) and the vesicular GABA transporter (VGAT) in neurons of the anteroventral periventricular nucleus and the rostral portion of the periventricular arcuate nucleus (ARC). In order to determine the percentage of coexpression between kisspeptins and VGAT positive cells, female mice who express cre recombinase enzyme under VGAT transcriptional control and cre recombinase induced green fluorescent reporter protein (GFP) will be evaluated. The animals will have their estrous cycles observed, and after the detection of regularity, the females will be selected for experiments in different stages of the estrous cycle: diestrus, proestrus and estrus. After transcardiac perfusion in the specific stages of the estrous cycle, the brains will be removed, processed and subjected to immunohistochemistry procedure. Considering kisspeptins are the main activity modulators of GnRH neurons and that the Kiss1 expressing neurons of the ARC are thought to be responsible for maintaining the negative feedback mechanism in the estrous cycle, verifying the percentage of coexpression between kisspeptin and GABAergic cells may help clarify the possible joint modulation of these neurotransmitters in the maintenance of the estrous cycle.
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