Involvement of alpha 2-adrenoceptors in mechanism of intragastric nicotine protection against ethanol injury in rat stomach
| Autor: | Felix W. Leung, Margaret Baker, John Kao, Kazuo Endoh |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Male
medicine.medical_specialty Nicotine Physiology Adrenergic beta-Antagonists Drug Evaluation Preclinical Blood Pressure Butoxamine Rats Sprague-Dawley Internal medicine Receptors Adrenergic beta medicine Prazosin Animals Drug Interactions Adrenergic alpha-Antagonists Metoprolol Analysis of Variance Gastric Juice Ethanol Chemistry Stomach Gastroenterology Antagonist Receptors Adrenergic alpha Yohimbine Rats medicine.anatomical_structure Endocrinology Mechanism of action Gastric Mucosa medicine.symptom medicine.drug |
| Zdroj: | Digestive diseases and sciences. 38(4) |
| ISSN: | 0163-2116 |
| Popis: | To elucidate the role of alpha- and beta-adrenoceptors in the mechanism of intragastric nicotine protection against ethanol-induced gastric mucosal injury, the following studies were performed. At 0.5-hr prior to the injury study, rats were pretreated with: subcutaneous control, prazosin (0.5 mg/kg) or yohimbine (5 mg/kg) to block alpha 1- or alpha 2-adrenoceptors; or intraperitoneal control, metoprolol (2 mg/kg) or butoxamine (4 mg/kg) to block beta 1- or beta 2-adrenoceptors, respectively. At 1-hr intervals, rats received intragastric vehicle or nicotine (4 mg/kg) and 40% ethanol (10 ml/kg). Total lengths of the linear gastric corpus mucosal lesions were measured by an unbiased observer using a caliper. In a separate study, 0.5-hr after subcutaneous control or yohimbine (5 mg/kg), rats were treated with intragastric vehicle or nicotine (4 mg/kg). One hour later, gastric mucus volume, gastric juice volume and pH, and titratable acid in the gastric juice were measured. In the rat stomach, the intragastric nicotine protection against 40% ethanol-induced mucosal injury was not blocked by selective alpha 1-(prazosin), beta 1-(metoprolol), or beta 2-(butoxamine) adrenoceptor antagonists. The protection was significantly reduced although not completely abolished by selective alpha 2-(yohimbine) adrenoceptor antagonist. Yohimbine also significantly reduced basal and nicotine-stimulated increase in gastric mucus volume. These data suggest that alpha 2-adrenoceptors are involved in the protective effect of intragastric nicotine against 40% ethanol-induced gastric mucosal injury possibly by a mucus-dependent mechanism. |
| Databáze: | OpenAIRE |
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