Modulation of intercellular calcium signaling by melatonin in avian and mammalian astrocytes is brain region-specific
Version of Record online: 31 OCT 2005
Copyright © 2005 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 493, Issue 3, pages 370–380, 19 December 2005
How to Cite
Peters, J. L., Earnest, B. J., Tjalkens, R. B., Cassone, V. M. and Zoran, M. J. (2005), Modulation of intercellular calcium signaling by melatonin in avian and mammalian astrocytes is brain region-specific. J. Comp. Neurol., 493: 370–380. doi: 10.1002/cne.20779
- Issue online: 31 OCT 2005
- Version of Record online: 31 OCT 2005
- Manuscript Accepted: 9 JUL 2005
- Manuscript Revised: 20 APR 2005
- Manuscript Received: 2 MAR 2005
- National Institute of Neurological Disorders and Stroke. Grant Number: PO1 NS-39546
Calcium waves among glial cells impact many central nervous system functions, including neural integration and brain metabolism. Here, we characterized the modulatory effects of melatonin, a pineal neurohormone that mediates circadian and seasonal processes, on glial calcium waves derived from different brain regions and species. Diencephalic and telencephalic astrocytes, from both chick and mouse brains, expressed melatonin receptor proteins. Further, using the calcium-sensitive dye Fluo-4, we conducted real-time imaging analyses of calcium waves propagated among mammalian and avian astrocytes. Mouse diencephalic astrocytic calcium waves spread to an area 2–5-fold larger than waves among avian astrocytes and application of 10 nM melatonin caused a 32% increase in the spread of these mammalian calcium waves, similar to the 23% increase observed in chick diencephalic astrocytes. In contrast, melatonin had no effect on calcium waves in either avian or mammalian telencephalic astrocytes. Mouse telencephalic calcium waves radially spread from their initiation site among untreated astrocytes. However, waves meandered among mouse diencephalic astrocytes, taking heterogeneous paths at variable rates of propagation. Brain regional differences in wave propagation were abolished by melatonin, as diencephalic astrocytes acquired more telencephalon-like wave characteristics. Astrocytes cultured from different brain regions, therefore, possess fundamentally disparate mechanisms of calcium wave propagation and responses to melatonin. These results suggest multiple roles for melatonin receptors in the regulation of astroglial function, impacting specific brain regions differentially. J. Comp. Neurol. 493:370–380, 2005. © 2005 Wiley-Liss, Inc.