Mechanically-induced Ca2+waves in RTEC plated on collagen or LM-332/collagen. Pseudo-colour maps of increases in [Ca2+]i in RTEC over time after mechanical stimulation of a single ciliated RTEC (arrow) are shown. Each horizontal image sequence displays approximate [Ca2+]i concentrations (see inset) beginning at 1 sec and following at 5 and 9 sec after mechanical stimulation. White lines in each panel approximate cell boundaries. Two separate pseudo-colour scale bars are depicted for A, B; and C – F. The first three panels represent typical Ca2+ waves in RTEC grown on collagen matrix under control conditions (A), treatment with gap27 (B), or treatment with apyrase (C). The last three panels represent typical Ca2+ waves in RTEC grown on LM-332/collagen matrix under control conditions (D), treatment with gap27 (E), or treatment with apyrase (F). Although intercellular Ca2+ communication is conserved in RTEC grown on collagen and LM-332/collagen matrices, the sensitivity to inhibitors show that the mechanism of communication is altered: RTEC grown on collagen propagate Ca2+ waves via gap junctions, whereas RTEC grown on LM-332/collagen propagate Ca2+ waves via extracellular nucleotide release.