Carbonic anhydrases and mucosal vanilloid receptors help mediate the hyperemic response to luminal CO2 in rat duodenum.

Background & Aims: The duodenal mucosa is exposed to PCO(2) >200 mm Hg due to the luminal mixture of gastric acid with secreted bicarbonate, which augments mucosal protective mechanisms. We examined the hyperemic response to elevated luminal PCO(2) in the duodenum of anesthetized rats luminally exposed to high CO(2) saline to help elucidate luminal acid-sensing mechanisms.

Methods: Blood flow was measured by laser Doppler, and intracellular pH of epithelial cells by measured by ratio microimaging.