Acid transport through channels in the mucous layer of rat stomach.

Abstract

We have reported previously that secreted acid moves through the mucous layer in restricted areas above the gastric crypts. The aim of this study was to visualize and study the dynamics of this event. Anesthetized rats prepared for intravital microscopy of the gastric mucosa were divided in the following groups with respect to acid secretion: spontaneous; stimulated (pentagastrin, 40 microg. kg(-1). h(-1)); transiently inhibited (omeprazole, 400 micromol. kg(-1) for 7 days); and totally inhibited (omeprazole, 3 x 200 micromol. kg(-1) for 7 days). The mucus was stained with Congo red (blue, pH < 3; red, pH > 5.2), and photographs were taken through a stereomicroscope. During acid secretion, blue-colored crypt openings with attached thread-like (5-7 microm wide) structures (designated channels) were seen passing from the crypt openings through the mucus to the lumen. Red-colored channels and crypt openings were observed when acid secretion was transiently inhibited. Red-colored crypt openings but no channels were found after total inhibition of acid secretion for a week. The results suggest that secreted acid is transported through channels within the mucus. These channels are probably created by the high intraglandular pressure pushing acid and glandular mucus into the gel.