title: Carbon monoxide insensitivity of gastric acid secretion.
abstract: By the use of hyperbaric conditions, it is possible to obtain high CO/O2 while maintaining O2 tension at a level that is not in itself inhibitory of acid secretion in the isolated frog gastric mucosa. Free solution CO/O2 of up to 10:1 only inhibit acid secretion about 20%, less than expected. Considerations of O2 diffusion into a respiring tissue bounded by unstirred layers predict a CO/O2 at the terminal oxidase ranging from 12 to 64 under various conditions and positions in the tissue, with predicted inhibitions between 55 and 86%. The inhibition observed is light reversible, affects potential difference and resistance in a consistent manner but is never very large. In the absence of O2, the CO-cytochrome alpha 3 complex can be demonstrated spectrophotometrically. Among other possible explanations for these observations, it is suggested that this tissue may contain an inhibitor-insensitive oxidase for a portion of the cytochrome system directly involved in acid secretion.
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000494:pharmacology*; D003580:Cytochromes / Q000378:metabolism; D005750:Gastric Juice / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D006931:Hyperbaric Oxygenation; D066298:In Vitro Techniques; D010101:Oxygen Consumption; D011892:Rana catesbeiana / Q000378:metabolism
chemical_list: D003580:Cytochromes; D002248:Carbon Monoxide