Cholinergic blockade inhibits gastro-oesophageal reflux and transient lower oesophageal sphincter relaxation through a central mechanism

Background-Atropine, an anticholinergic agent with central and peripheral actions, reduces gastro-oesophageal reflux (GOR) in normal subjects and patients with gastro-oesophageal reflux disease (GORD) by inhibiting the frequency of transient lower oesophageal sphincter relaxation (TLOSR). Aims-To compare the effect of methscopolamine bromide (MSB), a peripherally acting anticholinergic agent, with atropine on the rate and mechanism of GOR in patients with GORD. Methods-Oesophageal motility and pH were recorded for 120 minutes in 10 patients with GORD who were studied on three separate occasions. For the first two recording periods, either atropine (15 mu g/kg bolus, 4 mu g/kg/h infusion) or saline were infused intravenously. MSB (5 mg orally, four times daily) was given for three days prior to the third recording period. Results-Atropine significantly reduced basal LOS pressure (12.6 (0.17) mm Hg to 7.9 (0.17) mm Hg), and the number of TLOSR (8.1 (0.56) to 2.8 (0.55)) and reflux episodes (7.0 (0.63) to 2.0 (0.43)) (p<0.005 for all comparisons). MSB reduced basal LOS pressure (12.6 (0.17) to 8.7 (0.15) mm Hg, p<0.005), but had no effect on the frequency of TLOSR (8.1 (0.56) to 7.5 (0.59)) and reflux episodes (7.0 (0.63) to 4.9 (0.60)) (p>0.05). Conclusion-In contrast to atropine, MSE has no effect on the rate of TLOSR or GOR in patients with GORD. Atropine induced inhibition of TLOSR and GOR is most likely mediated through a central cholinergic blockade.