title: Non-genomic action of vitamin D3 on N-methyl-D-aspartate and kainate receptor-mediated actions in juvenile gonadotrophin-releasing hormone neurons.
abstract: Vitamin D is a versatile signalling molecule that plays a critical role in calcium homeostasis. There are several studies showing the genomic action of vitamin D in the control of reproduction; however, the quick non-genomic action of vitamin D at the hypothalamic level is not well understood. Therefore, to investigate the effect of vitamin D on juvenile gonadotrophin-releasing hormone (GnRH) neurons, excitatory neurotransmitter receptor agonists N-methyl-D-aspartate (NMDA, 30μM) and kainate (10μM) were applied in the absence or in the presence of vitamin D3 (VitaD3, 10nM). The NMDA-mediated responses were decreased by VitaD3 in the absence and in the presence of tetrodotoxin (TTX), a sodium-channel blocker, with the mean relative inward current being 0.56±0.07 and 0.66±0.07 (P<0.05), respectively. In addition, VitaD3 induced a decrease in the frequency of gamma-aminobutyric acid mediated (GABAergic) spontaneous postsynaptic currents and spontaneous postsynaptic currents induced by NMDA application with a mean relative frequency of 0.595±0.07 and 0.56±0.09, respectively. Further, VitaD3 decreased the kainate-induced inward currents in the absence and in the presence of TTX with a relative inward current of 0.64±0.06 and 0.68±0.06, respectively (P<0.05). These results suggest that VitaD3 has a non-genomic action and partially inhibits the NMDA and kainate receptor-mediated actions of GnRH neurons, suggesting that VitaD3 may regulate the hypothalamic-pituitary-gonadal (HPG) axis at the time of pubertal development.
authors.affiliation: Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Duckjin Dong, Jeonju, Jeonbuk 561-756, South Korea.
authors.forename: Pravin
authors.initials: P
authors.lastname: Bhattarai
authors.affiliation: Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Duckjin Dong, Jeonju, Jeonbuk 561-756, South Korea.
authors.forename: Janardhan P
authors.initials: JP
authors.lastname: Bhattarai
authors.affiliation: Department of Pediatrics, Chonbuk National University Medical School, and Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Institute of Chonbuk National University Hospital, Duckjin Dong, Jeonju, Jeonbuk 561-756, South Korea.
authors.forename: Min Sun
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Duckjin Dong, Jeonju, Jeonbuk 561-756, South Korea.
authors.forename: Seong Kyu
authors.initials: SK
authors.lastname: Han
mesh_terms: D000818:Animals; D002762:Cholecalciferol / Q000378:metabolism*; D044127:Epigenesis, Genetic; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000378:metabolism; D008297:Male; D008822:Mice, Transgenic; D016202:N-Methylaspartate / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000378:metabolism; D055495:Neurogenesis; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011301:Preoptic Area / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018092:Kainic Acid Receptors / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D055366:Synaptic Potentials / Q000187:drug effects
chemical_list: D002762:Cholecalciferol; D007987:Gonadotropin-Releasing Hormone; D049452:Green Fluorescent Proteins; D007608:Kainic Acid; D016202:N-Methylaspartate; D009419:Nerve Tissue Proteins; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; D026941:Sodium Channel Blockers