Intercellular Ca(2+) waves in rat hippocampal slice and dissociated glial-neuron cultures mediated by nitric oxide

Nitric oxide (NO) may participate in cell-cell communication in the brain by generating intercellular Ca(2+) waves. In hippocampal organotypic and dissociated glial-neuron (>80% glia) cultures local applications of aqueous NO induced slowly propagating intercellular Ca(2+) waves. In glial cultures, Ca(2+) waves and Mn(2+) quench of cytosolic fura-2 fluorescence mediated by NO were inhibited by nicardipine, indicating that NO induces Ca(2+) influx in glia which is dihydropyridine-sensitive. As NO treatments also depolarised the plasma membrane potential of glia, the nicardipine-sensitive Ca(2+) influx might be due to the activation of dihydropyridine-sensitive L-type Ca(2+) channels. Both nicardipine-sensitive intercellular Ca(2+) waves and propagating cell depolarisation induced by mechanical stress of individual glia were inhibited by pretreating cultures with either an NO scavenger or N(G)-methyl-L-arginine. Results demonstrate that NO can induce Ca(2+) waves in hippocampal slice cultures, and that Ca(2+) influx coupled to NO-mediated membrane depolarisation might assist in fashioning their spatio-temporal dynamics.