Ablation of primary afferent neurons by neonatal capsaicin treatment reduces the susceptibility of the portal hypertensive gastric mucosa to ethanol-induced injury in cirrhotic rats

• Published in: European journal of pharmacology 2008-07, Vol.589 (1-3), p.245-250
• Main Authors: Camara, Paula R.S., Ferraz, Gerson J.N., Franco-Penteado, Carla F., Sbragia-Neto, Lourenco, Meirelles, Luciana R., Teixeira, Simone A., Muscara, Marcelo N., Velloso, Licio A., Antunes, Edson, Ferraz, Jose G.P.
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - drug effects; Capsaicin; Capsaicin - pharmacology; Cardiology. Vascular system; Cirrhosis; Common Bile Duct - surgery; Ethanol - toxicity; Gastric Mucosa - blood supply; Gastric Mucosa - drug effects; Gastric Mucosa - enzymology; Gastric Mucosa - innervation; Gastric Mucosa - pathology; Gastroenterology. Liver. Pancreas. Abdomen; Gene Expression Regulation, Enzymologic - drug effects; Hypertension, Portal - metabolism; Hypertension, Portal - pathology; Hypertension, Portal - physiopathology; Ligation; Liver - drug effects; Liver - pathology; Liver Cirrhosis, Experimental - metabolism; Liver Cirrhosis, Experimental - pathology; Liver Cirrhosis, Experimental - physiopathology; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Male; Medical sciences; Neurokinin-1 Receptor Antagonists; Neurons, Afferent - drug effects; Neurons, Afferent - metabolism; Nitric Oxide Synthase - genetics; Nitric Oxide Synthase - metabolism; Other diseases. Semiology; Pharmacology. Drug treatments; Portal hypertension; Portal hypertensive gastropathy; Portal Pressure - drug effects; Prostaglandin-Endoperoxide Synthases - genetics; Prostaglandin-Endoperoxide Synthases - metabolism; Rats; Rats, Wistar; Receptors, Neurokinin-1 - metabolism; Regional Blood Flow - drug effects; RNA, Messenger - metabolism; Signal Transduction - drug effects; Tachykinin; Time Factors
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/j.ejphar.2008.05.004

Primary sensory afferent neurons modulate the hyperdynamic circulation in cirrhotic rats with portal hypertension. The stomach of cirrhotic rats is prone to damage induced by ethanol, a phenomenon associated with reduced gastric hyperemic response to acid-back diffusion. The aim of this study was to examine the impact of ablation of capsaicin-sensitive neurons and the tachykinin NK1 receptor antagonist A5330 on the susceptibility of the portal hypertensive gastric mucosa to ethanol-induced injury and its effects on gastric cyclooxygenase (COX) and nitric oxide synthase (NOS) mRNA expression. Capsaicin was administered to neonatal, male, Wistar rats and the animals were allowed to grow. Cirrhosis was then induced by bile duct ligation in adult rats while controls had sham operation. Ethanol-induced gastric damage was assessed using ex vivo gastric chamber experiments. Gastric blood flow was measured as well as COX/NOS mRNA expression. Topical application of ethanol produced significant gastric damage in cirrhotic rats compared to controls, which was reversed in capsaicin- and A5330-treated animals. Mean arterial and portal pressure was normalized in capsaicin-treated cirrhotic rats. Capsaicin and A5330 administration restored gastric blood flow responses to topical application of ethanol followed by acid in cirrhotic rats. Differential COX and NOS mRNA expression was noted in bile duct ligated rats relative to controls. Capsaicin treatment significantly modified gastric eNOS/iNOS/COX-2 mRNA expression in cirrhotic rats. Capsaicin-sensitive neurons modulate the susceptibility of the portal hypertensive gastric mucosa to injury induced by ethanol via tachykinin NK1 receptors and signalling of prostaglandin and NO production/release.