Melatonin elicits protein kinase C-mediated calcium response in immortalized GT1-7 GnRH neurons


Kelestimur H., Ozcan M., Kacar E., Alcin E., Yilmaz B., AYAR A.

BRAIN RESEARCH, vol.1435, pp.24-28, 2012 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 1435
  • Publication Date: 2012
  • Doi Number: 10.1016/j.brainres.2011.11.040
  • Title of Journal : BRAIN RESEARCH
  • Page Numbers: pp.24-28
  • Keywords: Melatonin, Calcium signaling, GT1-7 cell, MEDIOBASAL HYPOTHALAMUS, GENE-EXPRESSION, SERUM MELATONIN, SECRETION, CURRENTS, PUBERTY, SYSTEM, PINEAL

Abstract

Melatonin is suggested to have effects on hypothalamic-pituitary-gonadal (HPG) axis. The pulsatile pattern of GnRH release, which results in the intermittent release of gonadotropic hormones from the pituitary, has a critical importance for reproductive function but the factors responsible from this release pattern are not known. Calcium is a second messenger involved in hormone release. Therefore, investigation of the effects of melatonin on intracellular free calcium levels ([Ca2+](i)) would provide critical information on hormone release in immortalized GnRH neurons. The pattern of melatonin-induced intracellular calcium signaling was investigated by fluorescence calcium imaging using the immortalized GnRH-secreting GT1-7 hypothalamic neurons. Melatonin caused a significant increase in [Ca2+](i), which was greatly blocked by luzindole, a melatonin antagonist, or attenuated by pre-treatment with protein kinase C inhibitor. This study suggests that melatonin seems to have a direct effect on GnRH neurons. (C) 2011 Elsevier B.V. All rights reserved.