Abstract

The effects of the beta-1 adrenergic agonist prenalterol and the beta-2 adrenergic agonist terbutaline on oesophageal peristalsis were studied in nine healthy volunteers with pressures recorded in the proximal, middle, and distal oesophagus. Two doses of the agonists were given after pretreatment with placebo, propranolol, or metoprolol in a double blind randomised fashion. Terbutaline 0.25 +/- 0.25 mg iv decreased peristaltic pressure in middle oesophagus from 8.1 +/- 1.1 to 5.1 +/- 0.8 kPa (p less than 0.01) and in the distal oesophagus from 9.5 +/- 1.0 to 4.7 +/- 0.6 kPa (p less than 0.001). Peristaltic velocity was decreased in the distal oesophagus after terbutaline from 3.3 +/- 0.2 cm/sec to 2.9 +/- 0.2 cm/sec (p less than 0.05). Prenalterol 1 mg iv was followed by a decrease of peristaltic pressure in the middle oesophagus from 10.2 +/- 1.3 to 7.7 +/- 1.1 kPa (p less than 0.01) and a decrease of peristaltic velocity in upper oesophagus from 3.6 +/- 0.2 to 3.3 +/- 0.1 cm/sec (p less than 0.05) while no significant changes were seen in the distal oesophagus. Pretreatment with the beta-1 blocker metoprolol 15 mg iv blocked the effects of prenalterol 1 mg iv but not the effects of terbutaline. Propranolol 10 mg iv blocked the effects of terbutaline on peristaltic pressure. After metoprolol infusion mean distal peristaltic amplitude was 11.9 +/- 0.8 kPa compared with 8.5 +/- 1.2 kPa after placebo (p less than 0.01). It is concluded that both beta-1 and beta-2 adrenoceptor stimulation significantly decrease oesophageal peristaltic pressure in man. The body of the oesophagus seems to be under beta adrenergic inhibitory influence under physiological conditions.