Stimulation ofChR2 positive astrocytesincreases glial cells calcium transients frequency.

Abstract

<p>Cortical glial culture were co-incubated in fura-2-AM (<b>A</b>) and fluo-3-AM (<b>B</b>) and Ca²⁺ transients were monitored during UV [excitation (ex)380±20 nm] and blue light [excitation (ex) 470±20 nm] stimulation (200 ms light pulse @ 0.5 Hz; 10 min UV→10 min blue→10 min UV). The star (<b>*</b>) indicates the ChR-2 positive astrocyte. <b>C</b>, Time course of ChR-2 negative astrocyte during UV (left panel) and blue (right panel) illumination. Fura-2 downward peak indicates [Ca²⁺]_i increase, fluo-3 upward peak indicates [Ca²⁺]_i increase. <b>D</b>, Stimulation of the ChR-2 positive astrocyte with 470 nm light (blue column)increased calcium waves frequency to 566.7%±124.2% (UV vs Blue, paired t test p = 0.0002 – Blue vs UV, paired t test p = 0.0048). <b>E</b>,The increased Ca²⁺ waves frequency mediated by stimulation of ChR2 positive astrocyte was significantly reduced by APV 50 µM (UV vs Blue, paired t test p<0.0001 – Blue vs Blue+APV, paired t test p = 0.0019). Values are means ±SEM.</p