Gastric blood flow and acid secretion: problems of the methodology and regulatory mechanisms

Methods for proper measurement of gastric mucosal blood flow (MBF) in animal experiments or in clinical studies are critically reviewed. It can be stated that none of the techniques hitherto published fulfill all the criteria for proper measurement of the mucosal blood flow and concomitant acid production in the stomach. Some give an estimate of local blood flow changes (e.g. H2 gas clearance, laser Doppler flowmetry) in man without the possibility of simultaneous acid measurement. The 99mTc-MAP clearance technique developed by the authors reflects changes in both parameters and may also be used in clinical studies, when limitations of the method are taken into consideration. As a rule we assume that acid production and mucosal blood flow may change independently. The effects of various bioactive substances and drugs on both parameters are analysed. It seems that many contradictory findings have arisen because of differences in technique and experimental animals used.