Relaxation of Lower .Esophageal Sphincter and Stimulation of Gastric Secretion and Diuresis by Antiasthmatic Xanthines

Abstract

SUMMARY The study was designed to obtain information on selected extrapulmonary effects of enprofylline, an adenosine-non-blocking alkylxanthlne that Is about 5 times more potent as a bron­ chodilator than the adenosine receptor antagonist theophylline. Effects of theophylline (5.0 mg/kg) on lower esophageal sphincter pressure (LESP), gastric secretion, and diuresis and of enprofylline (1.5 mg/kg Intravenously producing about 21'g/ml plasma) were examined In 8 healthy volunteers. Enprofyiline and theophylline decreased LESP (by 5.0 ± 2.6 mm Hg, mean ± SO, P < 0.001, and by 5.8 ± 2.7 mmHg, p < 0.001, respectively), but only theophylline stimulated gastric secretion (volume p < 0.01 and acidity p < 0.01) and urine production (volume p < 0.01 and sodium chloride excretion p < 0.01). Neither xanthine affected plasma gastrin. Enprofylline and theophylline can be expected to have a similar ability to reduce the barrier to gastroesophageal reflux, but only the latter would have additional stimulant effects on gastric secretion and diuresis. These findings may have clinical significance and suggest a role for adenosine in regulating gastric secretion (and diure­ sis) but not LESP. AM REV RESPIR DIS 1985; 131:26-31