Sildenafil, a phosphodiesterase-5 inhibitor, delays gastric emptying and gastrointestinal transit of liquid in awake rats.
We studied the effect of sildenafil on gastric emptying (GE) and gastrointestinal (GI) transit in awake rats. After cervical vessel cannulation and 24 hr of fasting, the animals received an intravenous (IV) injection of sildenafil (4 mg/kg) or vehicle. Next they were gavage fed (1.5 ml) with a test meal (phenol red in 5% glucose solution, 0.5 mg/ml) and sacrificed 10, 20, or 30 min later. Experimental and control subsets consisted of 5-10 rats. Gastric and proximal, medial, and distal small intestine dye retentions (GDR and IDR, respectively) were obtained by spectrophotometry. Data were compared by ANOVA and Student-Newman-Keuls test. In sildenafil-treated animals, GDR increased (P < 0.05) by 20.3%, 46.9%, and 55,5% while medial IDR decreased (P < 0.05) by 35.1%, 43.4%, and 41.6%, respectively, at 10, 20, and 30-min intervals. Proximal and distal IDR values did not change in sildenafil-treated animals. Mean arterial pressure (MAP) decreased 25% (P < 0.05) right after sildenafil administration but normalized afterwards while in controls MAP remained unchanged. In conclusion, sildenafil delays GE and GI transit of a liquid meal while transiently decreases MAP in awake rats.
de Rosalmeida
Mauro Cabral
MC
Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil.
Saraiva
Luciana Duarte Sobreira
LD
da Graça
José Ronaldo Vasconcelos
JR
Ivo
Bruno Barreto
BB
da Nóbrega
Marcel Vieira
MV
Gondim
Francisco Assis Aquino
FA
Rola
Francisco Hélio
FH
dos Santos
Armenio Aguiar
AA
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004396:Coloring Agents / Q000493:pharmacokinetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005746:Gastric Emptying / Q000187:drug effects*; D005772:Gastrointestinal Transit / Q000187:drug effects*; D008297:Male; D009853:Omeprazole / Q000494:pharmacology; D010637:Phenolsulfonphthalein / Q000493:pharmacokinetics; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011687:Purines; D051381:Rats; D017208:Rats, Wistar; D000068677:Sildenafil Citrate; D013450:Sulfones
D004396:Coloring Agents; D004791:Enzyme Inhibitors; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D010637:Phenolsulfonphthalein; D009853:Omeprazole