Leptin activates cytosolic calcium responses through protein kinase-C dependent mechanism in immortalized RFamide-related peptide-3 neurons


BRAIN RESEARCH, vol.1601, pp.8-14, 2015 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 1601
  • Publication Date: 2015
  • Doi Number: 10.1016/j.brainres.2014.12.053
  • Journal Name: BRAIN RESEARCH
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.8-14
  • Karadeniz Technical University Affiliated: Yes


RFamide-related peptide-3 (RFRP-3), a mammalian ortholog of avian gonad tropin-inhibitory hormone (GnIH), seems to be an important regulator of the hypothalamus-pituitary-gonadal (HPG) reproductive axis. Leptin, a permissive hormonal regulator of fertility, provides energy signal to brain. According to current view, leptin does not act directly on gonadotrophin-releasing hormone (GnRH) neurons. RFRP-3 neurons have been shown to express leptin receptors. The goal of the present study was to examine whether leptin acts through RFRP-3 neurons to modulate activity of the GnRH neurons. For this aim, the effects of leptin on intracellular free Ca2+ levels ([Ca2+](i)) in RFRP-3 neurons were investigated by using in vitro calcium imaging system. In the present study, rHypoE-7 cell line was used as a model to explore the effects of leptin on RFRP-3 neurons. rHypoE-7 cells were placed on glass coverslip and loaded with 1 mu M Fura-2 AM. [Ca2+](i) responses were quantified by the changes in 340/380 ratio. Leptin (0.1-10 mu M) caused increases in [Ca2+](i) in a dose-dependent manner. The changes in [Ca2+](i) were significantly attenuated by pretreatment with protein kinase C inhibitor. These results demonstrate that leptin activates intracellular calcium signaling in RFRP-3 neurons through PKC-dependent pathway, and thus leptin may exert its effect on GnRH neurons by means of RFRP-3 cells. (C) 2015 Elsevier B.V. All rights reserved.