Activation of P2Y receptors causes strong and persistent shrinkage of C11-MDCK renal epithelial cells

persistent shrinkage of C11-MDCK renal epithelial cells. Am J Physiol Cell Physiol 301: C403–C412, 2011. First published May 11, 2011; doi:10.1152/ajpcell.00018.2011.—Purinergic receptors activate diverse signaling cascades and regulate the activity of cell volume-sensitive ion transporters. However, the effects of ATP and other agonists of P2 receptors on cell volume dynamics are only scarcely studied. In the present work, we used the recently developed dual-image surface reconstruction technique to explore the influence of purinergic agonists on cell volume in the C11-Madin-Darby canine kidney cell line resembling intercalated cells from kidney collecting ducts. Unexpectedly, we found that ATP and UTP triggered very robust (55–60%) cell shrinkage that lasted up to 2 h after agonist washout. Purinergic regulation of cell volume required increases in intracellular Ca2 and could be partially mimicked by the Ca2-ionophore ionomycin or activation of protein kinase C by 4-phorbo