Beta adrenergic modulation of human upper intestinal propulsive forces

Area of Science:

• Gastroenterology
• Pharmacology
• Physiology

Background:

• Beta-adrenoceptor blockade is known to accelerate small intestinal transit.
• The mechanism behind this acceleration, particularly concerning propulsive force, remains unclear.

Purpose of the Study:

• To investigate whether increased intraluminal aboral propulsive force contributes to beta-adrenoceptor blockade-induced transit acceleration.
• To test the hypothesis that beta-blockers enhance the propulsive force of intestinal contractions.

Main Methods:

• A double-blind, randomized, placebo-controlled study in 10 healthy volunteers.
• Oral administration of 100 mg atenolol (selective beta-1 antagonist) or placebo.
• Measurement of intestinal contraction frequency and propulsive force using manometry and a traction force detector.

Main Results:

• Atenolol significantly increased the propulsive force of both propagating and stationary intestinal contractions.
• Mean force per traction event increased significantly after atenolol administration (p < 0.05).
• No significant change was observed in the frequency of intestinal contractions (p > 0.05).

Conclusions:

• Beta-adrenoceptor blockade, specifically with atenolol, enhances the propulsive force of intestinal contractions.
• This increased propulsive force likely contributes to the accelerated gastrointestinal transit observed with beta-blockers.
• The findings suggest that sympathetic neural inhibition of intestinal tone may be removed by beta-blockade.