What is the effect of propranolol on intestinal smooth muscle?
The resting heart rate is approximately 110 beats per minute, with symptoms of palpitations. Propranolol has been taken continuously. May I ask what effect does propranolol have on intestinal smooth muscle?
Doctor's answer (1)
Propranolol is a non-selective beta receptor blocker primarily used in the treatment of cardiovascular diseases such as hypertension, angina pectoris, and arrhythmia. Its effects on intestinal smooth muscle mainly include:
1. Blocking beta receptors: By blocking beta-2 receptors, propranolol can reduce intestinal peristalsis and contraction, potentially providing adjunctive therapeutic effects for certain gastrointestinal disorders. For example, in patients with diarrhea or irritable bowel syndrome, propranolol can slow intestinal motility, prolong the retention time of food in the intestine, and thereby reduce bowel movements and improve diarrhea symptoms.
2. Reducing visceral nerve activity: Propranolol also affects the motility of small intestinal smooth muscle by decreasing visceral nerve activity. This reduces efferent impulses from the visceral nerves, further decreasing the contraction activity of smooth muscle in the small intestine.
3. Inhibiting calcium ion influx: Propranolol can inhibit the influx of calcium ions into small intestinal smooth muscle cells, lowering intracellular calcium ion concentration. Since calcium ions are key factors in smooth muscle contraction, this inhibitory effect directly leads to weakened contraction of the small intestinal smooth muscle.
