SEMI-INVASIVE LASER-DOPPLER FLOWMETRY TECHNIQUE - NEW APPLICATION FORRECORDINGS OF HEMODYNAMICS IN COMBINATION WITH MANOMETRY OF HUMAN SMALL-INTESTINE

A small-bowel manometry tube was supplied with two single-fiber microp robes, which recorded blood flow in the proximal small intestine by th e laser-Doppler flowmetry (LDF) technique. In all experiments, saline was infused intravenously as control during the first migrating motor complex (MMC) cycle, and a drug or another saline control given intrav enously during the second MMC cycle. Recordings were performed during phase I of MMC, i.e, when motor pattern showed quiescence. Adrenaline increased blood perfusion values by 140% in proximal duodenum and 95% in distal duodenum. The alpha(2)-adrenoceptor agonist clonidine decrea sed the corresponding values by 34 and 25%, respectively, while oxymet azoline decreased perfusion by 33 and 44% at the same levels. The beta -adrenoceptor agonist isoprenaline increased blood perfusion values by 172% in the proximal duodenum and 194% in the distal duodenum, wherea s the antagonist propranolol decreased the corresponding values by 45 and 52%, respectively. In a separate group of subjects, propranolol wa s given after adrenaline. The increase in blood perfusion regularly se en after adrenaline was blocked after propranolol administration. In c onclusion, our findings validate semi-invasive LDF technique for studi es of hemodynamics in human small intestine under basal motor conditio ns and in drug-induced blood flow changes.