Proposed cell model for P2Y, PKC and PI3-K regulation of ion transport by SCCD epithelium. Na+ is absorbed from endolymph by entry into the cytosol across the apical membrane via the epithelial Na+ channel (ENaC). Na+ is removed from the cytosol across the basolateral membrane by the Na+, K+-ATPase (Na+-pump); K+ entering the cell on the Na+, K+-ATPase recycles across the basolateral membrane via K+ channels. Activity of this Na+ absorptive mechanism is stimulated by activation of the glucocorticoid receptor (GR), by activity of phosphoinositide-3 kinase (PI3-K) and inhibited by activity of protein kinase C (PKC). Activation of the P2Y2 receptor (P2Y2-R) in the basolateral membrane reduces the barrier to ions of the tight junctions (TJ) and stimulates Cl- secretion.
Pondugula et al. BMC Research Notes 2010 3:100 doi:10.1186/1756-0500-3-100