Cell-to-cell propagation of intracellular signals fluorescently visualized with acridine orange in the gastric glands of guinea pigs

Secretion from the gastric gland involves the activation of various types of cells in a coordinated manner. In order to elucidate the mechanisms underlying the coordination of secretion, we studied live fluorescence images of guinea pig gastric glands stained with acridine orange (AO). On 2 μM AO staining, individual cells were characterized by metachromatic colors and various intensities of fluorescence. When the gland was stimulated with 100 μM of histamine, green fluorescence was transiently increased in parietal cells and intermediate cells and propagated along the gland for a long distance over many cells. Local stimulation in a couple of cells with histamine in the presence of suramin also induced propagation. However, the fluorescence response was suppressed by the addition of H-89, a protein kinase A inhibitor. These findings suggest that a cAMP-dependent signal propagates intercellularly through a variety of cells to induce coordinated secretion in the entire gastric gland.