Effects of aspirin-like drugs on canine gastric mucosal blood flow and acid secretion.

1. The effects of aspirin, paracetamol and benorylate were studied on gastric mucosal blood flow (MBF) and acid secretion in canine denervated gastric pouches. 2. Aspirin 20 mM in the unstimulated pouch had no effect; pentagastrin-stimulated acid output, but not MBF, was reduced. Aspirin buffered to pH 6 was ineffective. 3. Aspirin 3-50 mg/kg reaching the pentagastrin-stimulated pouch through the blood, increased acid secretion and MBF, but the MBF:secretion ratio was variably affected. 4. Paracetamol (10 or 20 mg/kg i.v., or 20 mM in the pouch) or benorylate (280 mg/kg orally) mainly had little effect. 5. Circular muscle strips from dog arteries were contracted by prostaglandins E2, F1alpha or F2alpha, and often slightly by indomethacine, but prostaglandin E1 produced variable effects. 6. These results do not favour the view that aspirin causes gastric bleeding in dogs by breakdown of blood vessels due to ischaemia following mucosal vasoconstriction.