Inhibitory effects of sildenafil on gastric motility and gastric slow waves in dogs

Abstract

The aim of this study was to investigate the effects of sildenafil on gastric motility and gastric slow waves in dogs. The study was performed in healthy dogs and composed of three experiments. The first experiment was designed to study the effects of sildenafil on gastric emptying and gastric slow waves. The second experiment was used to investigate the effects of sildenafil on gastric tone. The third experiment was used to study the effects of sildenafil on postprandial antral contractions. (i) Sildenafil did not alter gastric emptying of liquid. (ii) Sildenafil had no effects on dominant frequency and percentage of normal gastric slow waves. The dominant power of gastric slow waves was, however, significantly reduced with sildenafil (P < 0.02). (iii) Fasting gastric volume with sildenafil was significantly higher than that at baseline (P < 0.0005) or in the control session (P < 0.002). However, the postprandial gastric volume was not altered with sildenafil. (iv) Sildenafil inhibited gastric antral motility. The contraction index was 338.5 +/- 39.99 at baseline and 122.5 +/- 20.3 after the injection of sildenafil (P = 0.003). Sildenafil inhibits fundic tone and antral motility but does not seem to delay gastric emptying of liquid in dogs. The amplitude but not the frequency or regularity of the gastric slow wave is inhibited by sildenafil.

Sildenafil improves clinical signs and radiographic features in dogs with congenital idiopathic megaoesophagus: a randomised controlled trial

“…Endogenous NO induces smooth muscle relaxation through the synthesis of the second messenger cyclic guanosine monophosphate (cGMP). Sildenafil, a selective phosphodiesterase-type 5 (PDE-5) inhibitor, indirectly potentiates the action of endogenous NO by reducing cGMP degradation due to PDE-5 (Zhu and others 2007). Sildenafil is an effective vasodilator and is widely prescribed for the treatment of erectile disorders in man; however, it is also used to treat pulmonary hypertension, and it relaxes the smooth muscle of other organs such as the uterus (Méhats and others 2006) and the gallbladder (Degirmenci and others 2006).…”

Megaesôfago em cães - revisão de literatura

“…O óxido nítrico endógeno induz o relaxamento da musculatura lisa, presente em esfíncter esofágico inferior, através da síntese do monofosfato de guanosina cíclica do segundo mensageiro (cGMP) (ZHU et al, 2007).…”