The Extracellular Calcium-Sensing Receptor Is Expressed in Rat Microglia and Modulates an Outward K+ Channel.

Autor: Chattopadhyay, Naibedya, Ye, Chianping, Yamaguchi, Toru, Nakai, Masamichi, Kifor, Olga, Vassilev, Peter M., Nishimura, Robert N., Brown, Edward M.
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Zdroj: Journal of Neurochemistry; May99, Vol. 72 Issue 5, p1915-1922, 8p, 5 Black and White Photographs, 8 Graphs
Abstrakt: The calcium-sensing receptor (CaR) is a G protein-coupled receptor that “senses” extracellular calcium ions (Ca2+o) as an extracellular first messenger. In this report, we have shown that the CaR is expressed in primary cultures of microglial cells derived from rat brain as assessed by RT-PCR using four CaR-specific primer pairs followed by sequencing of the amplified products, by northern blot analysis using a CaR-specific probe, as well as by immunocytochemistry and western analysis utilizing a specific polyclonal anti-CaR antiserum. In addition, raising Ca2+o from 0.75 to 3.0 mM or addition of the polycationic CaR agonist neomycin or a “calcimimetic” CaR activator (R-467; NPS Pharmaceuticals) increased the open state probability (Po) of a Ca+-activated K+ channel having a unitary conductance of 84 ± 4 pS, indicating that the channel is modulated by the CaR. Therefore, our data strongly suggest that a functional CaR is expressed in cultured rat microglia, similar to that in parathyroid gland and kidney, which could potentially play an important role(s) in regulating microglial function. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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