Neuromedin U receptor-2 mRNA and HCN channels mRNA expression in NMU-sensitive neurons in rat hypothalamic paraventricular nucleus

We have characterized the neuromedin U (NMU)-sensitive neurons in the rat paraventricular nucleus (PVN) using whole-cell patch-clamp recordings and single-cell reverse transcription-multiplex polymerase chain reaction (single-cell RT-mPCR). Following completion of whole-cell recording, the NMU-sensitive neurons were examined for oxytocin (OT), vasopressin (VP), and corticotrophin-releasing hormone (CRH) mRNA expression using single-cell RT-mPCR. Of the NMU-sensitive neurons (n = 23), 82% expressed OT mRNA, 9% expressed VP mRNA, 9% did not express the detected specific phenotypes mRNA. Further, the NMU-sensitive neurons (23/23) predominantly expressed NMU-receptor 2 (NMUR-2) mRNA, co-expressed HCN1 channel mRNA, HCN2 channel mRNA, and HCN3 channel mRNA but not HCN4 channel mRNA. These results suggest that NMU modulates the function of the PVN putative parvocellular neurons and is involved in the regulation of OTergic and VPergic neurons by enhanced HCN ion channels activity via NMU-receptor 2.