Voltage-gated calcium channel types in cultured C. elegans CEPsh glial cells.

The four cephalic sensilla sheath (CEPsh) glial cells are important for development of the nervous system of Caenorhabditis elegans. Whether these invertebrate glia can generate intracellular Ca(2+) increases, a hallmark of mammalian glial cell excitability, is not known. To address this issue, we developed a transgenic worm with the specific co-expression of genetically encoded red fluorescent protein and green Ca(2+) sensor in CEPsh glial cells. This allowed us to identify CEPsh cells in culture and monitor their Ca(2+) dynamics. We show that CEPsh glial cells, in response to depolarization, generate various intracellular Ca(2+) increases mediated by voltage-gated Ca(2+) channels (VGCCs). Using a pharmacological approach, we find that the L-type is the preponderant VGCC type mediating Ca(2+) dynamics. Additionally, using a genetic approach we demonstrate that mutations in three known VGCC α(1)-subunit genes, cca-1, egl-19 and unc-2, can affect Ca(2+) dynamics of CEPsh glial cells. We suggest that VGCC-mediated Ca(2+) dynamics in the CEPsh glial cells are complex and display heterogeneity. These findings will aid understanding of how CEPsh glial cells contribute to the operation of the C. elegans nervous system.