On the cover: Toluidine blue-stained section (1 micron) of rat lung. Rat and mouse lungs were perfusion-fixed with glutaraldehyde in cacodylate buffer after treatment to activate the vanilloid transient receptor potential channel TRPV4 or store-operated channels. Lung blocks were post-fixed with osmium tetroxide and embedded in PolyBed 812 resin, then sections prepared for light microscopy. Morphomometric analysis of digital images from these sections was used to document that activation of TRPV4, but not store-operated channels, increased alveolar fluid volume fraction. See related article, page 988.