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Intracellular calcium elevation induced by extracellular application of cyclic-ADP-ribose or oxytocin is temperature-sensitive in rodent NG108-15 neuronal cells with or without exogenous expression of human oxytocin receptors.
- Source :
-
Journal of neuroendocrinology [J Neuroendocrinol] 2010 May; Vol. 22 (5), pp. 460-6. Date of Electronic Publication: 2010 Feb 12. - Publication Year :
- 2010
-
Abstract
- ADP-ribosyl cyclase and/or CD38 are activated after oxytocin receptor stimulation in the hypothalamus and pituitary in adult mice, leading to facilitation of oxytocin secretion. Although cyclic adenosine 5'-diphosphoribose (cADPR) primarily acts as an intracellular second messenger, it has been suggested that extracellular cADPR stimulates intracellular ryanodine receptors after internalisation via the nucleotide-transporting capacity of CD38 in fibroblasts and astrocytes. However, little is known about whether extracellular cADPR activates neurones. To address this question, we used a model neuronal cell line, NG108-15 mouse neuroblastoma x rat glioma hybrid cells possessing CD38 but not oxytocin receptors, and measured cytosolic free calcium concentrations ([Ca(2+)](i)). Extracellular application of cADPR to NG108-15 cells elevated [Ca(2+)](i) at 35 degrees C. The elevation was significantly enhanced when measured at 40 degrees C. The cADPR and heat-induced [Ca(2+)](i) increase were blocked under extracellular Ca(2+)-free conditions and by 2-aminoethoxydiphenyl borate, an antagonist of melastatin-related transient receptor potential channel 2 (TRPM2) cation channels. Reverse transcriptation-polymerase chain reaction analyses indicated that TRPM2 channels were expressed in NG108-15 cells. Application of oxytocin elevated [Ca(2+)](i) in NG108-15 cells transformed to transiently express cloned human oxytocin receptors. The oxytocin-induced [Ca(2+)](i) response was also enhanced by heat. These results indicate that the extracellular application of cADPR, together with heat, activates cation influx downstream of oxytocin receptor signalling in NG108-15 neuronal cells, and suggest the possible involvement of TRPM2 channels in oxytocin release in the mammalian brain.
Details
- Language :
- English
- ISSN :
- 1365-2826
- Volume :
- 22
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Journal of neuroendocrinology
- Publication Type :
- Academic Journal
- Accession number :
- 20163520
- Full Text :
- https://doi.org/10.1111/j.1365-2826.2010.01978.x