Fig. 5

The Cx hemichannel- and Panx-1 channel-mediated Ca²⁺ signaling depends on the activation of purinergic receptors. A Time course of the increase in [Ca²⁺]_i induced in primary cultures of astrocytes by 10 µM glutamate in control conditions and after the blockade of purinergic receptors with 100 µM PPADS or the inhibition of CALHM1 channels with 20 µM ruthenium red (RuR). B Analysis of the increase in ethidium uptake rate induced by glutamate in control conditions and in the presence of PPADS or RuR. The rate of ethidium uptake was assessed by calculating the slope of the increase in fluorescence intensity (expressed as arbitrary units, AU) along the time in basal conditions and during the stimulation with glutamate. C ATP release evoked by glutamate in control conditions and after the treatment with 100 µM N^ω-nitro-L-arginine (L-NA) to inhibit NO production, the mimetic peptide ^37,43Gap27 (Gap27, 100 µM) to block hemichannels formed by Cx37 or Cx43, ¹⁰Panx (100 µM) to block Panx1 channels or RuR. ATP was measured after 3 min of stimulation with glutamate. Numbers inside the bars indicate the n value. D Time course of the increase in [Ca²⁺]_i elicited by 100 nM ATP in primary cultures of astrocytes in control conditions and in the presence of ^37,43Gap27 or ¹⁰Panx. Values are means ± SEM. *P < 0.05 vs Control by one-way ANOVA plus Bonferroni post hoc test. ^†P < 0.05 vs Baseline by paired Student’s t-test