Mechanism of aggravation of mucosal injury by intravenous nicotine in rat stomach
| Autor: | G. L. Kauffman, Felix W. Leung, K. Endoh |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
Nicotine Physiology Prostaglandin Hyperemia Prostacyclin 6-Ketoprostaglandin F1 alpha Sodium Chloride Pharmacology Dinoprostone chemistry.chemical_compound Physiology (medical) medicine Gastric mucosa Animals Prostaglandin E2 Reactive hyperemia Analysis of Variance Hepatology business.industry Stomach Gastroenterology Rats Inbred Strains Rats Hypertonic saline medicine.anatomical_structure chemistry Gastric Mucosa Anesthesia Injections Intravenous business Hydrogen medicine.drug |
| Zdroj: | American Journal of Physiology-Gastrointestinal and Liver Physiology. 261:G1037-G1042 |
| ISSN: | 1522-1547 0193-1857 |
| Popis: | Endogenous prostaglandins and injury-induced hyperemia are important defense mechanisms in the gastric mucosa. In the rat stomach, we tested the hypotheses that an ulcer-promoting dose of intravenous nicotine 1) reduces ex vivo prostaglandin generation and 2) aggravates mucosal lesions by impairing injury-induced hyperemia. Anesthetized rats were given intravenous control or 4 or 40 micrograms.kg-1.min-1 nicotine infusion. In study 1, ex vivo generation of prostaglandin E2 and 6-ketoprostaglandin F1 alpha (stable metabolite of prostacyclin) was determined by vortexing the mucosal tissue, followed by radioimmunoassay. No significant difference in prostaglandin generation was found between the control and experimental groups. In study 2, intravenous nicotine (40 micrograms.kg-1.min-1) produced a significant rise (19 +/- 3%) in mean blood pressure and completely abolished the gastric hyperemia produced by intragastric saline (2 M). The extent of the associated gastric mucosal injury was significantly increased (from 5.3 +/- 0.8 to 17.4 +/- 5.2% of the corpus mucosa), while the maximum depth of the largest lesions was not affected by intravenous nicotine. The data confirm that the gastric hyperemia associated with gastric mucosal exposure to hypertonic saline plays an important role in limiting the extent of gastric mucosal damage. We conclude that in the rat stomach 1) an ulcer-promoting dose of intravenous nicotine does not significantly inhibit cyclooxygenase activity, and 2) the same does of intravenous nicotine exacerbates hypertonic saline-induced gastric mucosal injury by a mechanism that involves inhibition of injury-induced hyperemia. |
| Databáze: | OpenAIRE |
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