Objective: Sildenafil relaxes smooth muscle by blocking type 5 phosphodiesterase, which destroys nitric oxide-stimulated cyclic guanosine monophosphate. The aim of this study is to investigate the change of lower esophageal sphincter (LES) and body motility with the lapse of time after sildenafil infusion in normal male adults.
Methods: After basal esophageal manometry in eight healthy male adult volunteers, we infused a 50-mg tablet of sildenafil dissolved in water in the stomach through the manometry catheter and observed the changes of LES and body motility with the lapse of time. We randomized the study population into two groups, and esophageal manometry was repeated in LES and body sequence in four volunteers and in body and LES sequence in the other four volunteers immediately after sildenafil infusion.
Results: LES resting pressure significantly decreased after sildenafil infusion. The body peristaltic amplitude gradually decreased and eventually disappeared, and the latency increased significantly after sildenafil infusion in both the proximal and distal esophagus.
Conclusions: These data support that nitric oxide mediates LES relaxation and the timing of esophageal peristalsis. In the future, sildenafil can be tried in some esophageal motor disorders, which have defects in nitric oxide neuromuscular communication.