Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. Signal., 3 April 2012
Vol. 5, Issue 218, p. ra27
[DOI: 10.1126/scisignal.2002498]


Editor's Summary

Keeping Calcium Signals in the Processes
Although astrocytes, the most numerous form of glial cell in the brain, are electrically inexcitable, their ability to release chemical messengers and respond to such messengers with propagated calcium signals allows them to participate actively in the regulation of local blood flow and of synaptic efficacy. Here, Arizono et al. expressed a genetically encoded calcium indicator in neuron-astrocyte cocultures and hippocampal slices and found that, compared to the soma, astrocyte processes showed enhanced calcium responses to stimulation of the metabotropic glutamate receptor (mGluR). The enhanced calcium response observed in processes resulted from an increased density of mGluRs, rather than from differences in the distribution or sensitivity of the calcium release machinery. Analysis of the movement of single mGluR5s revealed a membrane barrier that selectively blocked the movement of mGluR5 between astrocyte somata and their processes. Noting that various neurological disorders are associated with abnormal calcium signaling in astrocytes, the authors speculate that the existence of this barrier—and thereby of compartmentalized calcium signals—could allow individual processes to regulate associated partners (synapses or blood vessels) independently, in the absence of a somatic calcium signal.

Citation: M. Arizono, H. Bannai, K. Nakamura, F. Niwa, M. Enomoto, T. Matsu-ura, A. Miyamoto, M. W. Sherwood, T. Nakamura, K. Mikoshiba, Receptor-Selective Diffusion Barrier Enhances Sensitivity of Astrocytic Processes to Metabotropic Glutamate Receptor Stimulation. Sci. Signal. 5, ra27 (2012).

Read the Full Text

Imaging calcium microdomains within entire astrocyte territories and endfeet with GCaMPs expressed using adeno-associated viruses.
E. Shigetomi, E. A. Bushong, M. D. Haustein, X. Tong, O. Jackson-Weaver, S. Kracun, J. Xu, M. V. Sofroniew, M. H. Ellisman, and B. S. Khakh (2013)
J. Gen. Physiol. 141, 633-647
   Abstract »    Full Text »    PDF »
Chronic hypoxia and VEGF differentially modulate abundance and organization of myosin heavy chain isoforms in fetal and adult ovine arteries.
M. C. Hubbell, A. J. Semotiuk, R. B. Thorpe, O. O. Adeoye, S. M. Butler, J. M. Williams, O. Khorram, and W. J. Pearce (2012)
Am J Physiol Cell Physiol 303, C1090-C1103
   Abstract »    Full Text »    PDF »
Science Signaling Podcast: 10 April 2012.
M. Nedergaard, K. Mikoshiba, and A. M. VanHook (2012)
Science Signaling 5, pc8
   Abstract »    Full Text »

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882