Prokineticin 2 regulates the electrophysiological activity of gonadotropin-releasing hormone neurons via direct signalling in adult female mice

Introduction: Prokineticin 2 (PK2) signaling to gonadotropin-releasing hormone (GnRH) neurons is essential for their embryonic migration from the nasal placode to the brain, and its disruption results in hypogonadotropic hypogonadism. Although PK2 has been implicated in the regulation of reproductive function in adult rodents, its direct cellular targets remain insufficiently defined. Here, we investigated whether GnRH neurons in adult female mice receive and functionally respond to PK2 signals.Methods: Whole-cell patch-clamp recordings were obtained from acute forebrain slices prepared from adult female GnRH-GFP mice. The effects of PK2 and prokineticin receptor antagonists on spontaneous firing and miniature postsynaptic currents (mPSCs) were assessed. Expression of PK2 receptor (PKR2) in GnRH neurons was examined using RNAscope in situ hybridization for simultaneous detection of PKR2 and GnRH mRNAs, followed by confocal laser microscopic analysis.Results: PK2 increased action potential firing and mPSC frequency in 42.9% (firing) and 42.1% (mPSC) of GnRH neurons. These effects were prevented by intracellular G-protein inhibition with GDP-β-S and by pharmacological blockade of prokineticin receptors using PKRA7 or PC27. Inhibition of nitric oxide synthase by NPLA also eliminated the PK2-induced elevation of mPSC frequency. RNAscope analysis revealed PKR2 mRNA expression in approximately one-third of GnRH neurons.Discussion: These findings demonstrate that PK2 directly enhances the excitability of a subset of GnRH neurons through PKR2-dependent mechanisms, identifying these neurons as functional targets of PK2 signaling in the mature female mouse brain.Conclusion: PK2 serves as a direct modulator of the reproductive neuroendocrine axis in adult female mice by activating PKR2 expressed in a subpopulation of GnRH neurons.