Impaired esophageal reactivity in adriamycin-induced rat esophageal atresia: An in vitro study

Purpose: The aim of this study was to investigate the reactivity of lower e sophageal smooth muscle in the Adriamycin-induced esophageal atresia (EA) r at model. Methods: The fetuses were divided into 3 groups. The control group was expo sed to saline. The second group comprised fetuses that were exposed to Adri amycin but in whom EA did not develop. The third group comprised of fetuses that were exposed to Adriamycin and EA was observed. The reactivity of dis tal esophageal strips was studied in organ chambers. Results: The tension was similar in all groups precontracted with carbachol for the study of relaxation to serotonin. Relaxation of lower esophageal s trips to serotonin was comparably unaffected in the control and Adriamycin- no EA groups, whereas it was significantly inhibited in the EA group with d ecreased E-max and pD(2) values. Contractile responses of esophageal smooth muscle to carbachol or 80 mmol/L KCl and relaxant responses to papaverine were similar in all groups. No change in agonist potency was observed among the groups. Conclusions: Our study showed impairment of serotonin-receptor-mediated rel axation; but not of cholinoceptor-mediated contraction of the lower esophag eal smooth muscle in the EA. Thus, impaired relaxant responses may be, at l east in part, a contributing factor in the esophageal dismotility seen in E A. Copyright (C) 2001 by W.B. Saunders Company.