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Evidence of involvement of neurone‐glia/neurone‐neurone communications via gap junctions in synchronised activity of KND y neurones
Author(s) -
Ikegami K.,
Minabe S.,
Ieda N.,
Goto T.,
Sugimoto A.,
Nakamura S.,
Inoue N.,
Oishi S.,
Maturana A. D.,
Sanbo M.,
Hirabayashi M.,
Maeda K.I.,
Tsukamura H.,
Uenoyama Y.
Publication year - 2017
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/jne.12480
Subject(s) - neurokinin b , gap junction , kisspeptin , arcuate nucleus , biology , microbiology and biotechnology , medicine , endocrinology , neuroscience , neuropeptide , hypothalamus , neurosecretion , confocal microscopy , gonadotropin releasing hormone , hormone , substance p , receptor , luteinizing hormone , intracellular
Pulsatile secretion of gonadotrophin‐releasing hormone (Gn RH )/luteinising hormone is indispensable for the onset of puberty and reproductive activities at adulthood in mammalian species. A cohort of neurones expressing three neuropeptides, namely kisspeptin, encoded by the Kiss1 gene, neurokinin B ( NKB ) and dynorphin A, localised in the hypothalamic arcuate nucleus ( ARC ), so‐called KND y neurones, comprises a putative intrinsic source of the Gn RH pulse generator. Synchronous activity among KND y neurones is considered to be required for pulsatile Gn RH secretion. It has been reported that gap junctions play a key role in synchronising electrical activity in the central nervous system. Thus, we hypothesised that gap junctions are involved in the synchronised activities of KND y neurones, which is induced by NKB ‐ NK 3R signalling. We determined the role of NKB ‐ NK 3R signalling in Ca 2+ oscillation (an indicator of neuronal activities) of KND y neurones and its synchronisation mechanism among KND y neurones. Senktide, a selective agonist for NK 3R, increased the frequency of Ca 2+ oscillations in cultured Kiss1 ‐ GFP cells collected from the mediobasal hypothalamus of the foetal Kiss1 ‐green fluorescent protein ( GFP ) mice. The senktide‐induced Ca 2+ oscillations were synchronised in the Kiss1 ‐ GFP and neighbouring glial cells. Confocal microscopy analysis of these cells, which have shown synchronised Ca 2+ oscillations, revealed close contacts between Kiss1 ‐ GFP cells, as well as between Kiss1 ‐ GFP cells and glial cells. Dye coupling experiments suggest cell‐to‐cell communication through gap junctions between Kiss1 ‐ GFP cells and neighbouring glial cells. Connexin‐26 and ‐37 mRNA were found in isolated ARC Kiss1 cells taken from adult female Kiss1 ‐ GFP transgenic mice. Furthermore, 18β‐glycyrrhetinic acids and mefloquine, which are gap junction inhibitors, attenuated senktide‐induced Ca 2+ oscillations in Kiss1 ‐ GFP cells. Taken together, these results suggest that NKB ‐ NK 3R signalling enhances synchronised activities among neighbouring KND y neurones, and that both neurone‐neurone and neurone‐glia communications via gap junctions possibly contribute to synchronised activities among KND y neurones.