Correlation between α₁–Adrenoceptors in Biopsy Specimens and Endoscopic Color Changes of Human Gastric Ulcer

α₁–Adrenoceptors were measured in the scar tissue (U) and marginal normal mucosa (C) of human gastric ulcers by radio-binding assay using [³H]-prazosin as the ligand. The specific radioactivity binding was calculated for the membrane-rich fractions of the U and C regions along with U/C ratio, and the relationship between the scar color tone and α–adrenoceptor binding levels was studied by conventional endoscopy and pharmacoendoscopy

The U/C ratio for red scars (mean: 92.2%) increased as redness decreased. White scars had a mean U/C ratio of 135.6%. For pharmacoendoscopic classes P₁ and P₂, which remained red after spraying epinephrine onto the scar, the mean U/C ratio was 86.8%. For the P₃ class, which turned pale after the application of epinephrine spray, the mean U/C ratio was 172.0%. The recurrence of peptic ulcers is more frequent when red scars ocAcur, assessed by conventional endoscopy, in the P₁ and₂ classes, evaluated by pharmacoendoscopy, than in white scars (P₃ class). As the α₁–adrenoceptor binding of [³H]-prazosin appears to be proportional to the maturity of vasculature tissue, the present data suggest this latter factor plays a key role in the recurrence of gastric ulcers and that pharmacoendoscopy allows for a more accurate prognosis of ulcer relapse than conventional endoscopy