Endothelial and nonendothelial cyclooxygenase mediate rabbit pial arteriole dilation by bradykinin
| Autor: | Karen A. Willoughby, Earl F. Ellis, S. F. Moore, J. R. Copeland, T. M. Tynan |
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| Rok vydání: | 1995 |
| Předmět: |
Male
Endothelium Physiology Bradykinin Prostaglandin Blood Pressure 6-Ketoprostaglandin F1 alpha Pharmacology Arginine Nitric Oxide Dinoprostone Microcirculation chemistry.chemical_compound Cerebrospinal fluid Physiology (medical) medicine Animals Cyclooxygenase Inhibitors Microvessel Aspirin biology Chemistry Cerebral Arteries Acetylcholine Vasodilation Arterioles NG-Nitroarginine Methyl Ester medicine.anatomical_structure Eicosanoid Prostaglandin-Endoperoxide Synthases Cerebrovascular Circulation Anesthesia biology.protein Amino Acid Oxidoreductases Endothelium Vascular Rabbits Cyclooxygenase Nitric Oxide Synthase Cardiology and Cardiovascular Medicine |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 268:H458-H466 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.1995.268.1.h458 |
| Popis: | Aspirin (acetylsalicylic acid, ASA) was administered to rabbits in an attempt to inhibit selectively endothelial cyclooxygenase activity and therefore to determine its role in bradykinin-induced radical-mediated dilation of cerebral arterioles. With the use of the cranial window technique in anesthetized rabbits, pial arteriolar diameters were recorded in response to topically applied bradykinin, acetylcholine, and ventilation with 10% O2-9% CO2 gas mixture. Prostaglandins were measured in isolated cerebral microvessels and cerebrospinal fluid (CSF) using radioimmunoassay. Microvessel prostaglandin production was reduced significantly by 90 mg/kg i.v. ASA, whereas acetylcholine-stimulated increases of CSF prostaglandins were not similarly affected. This treatment reduced bradykinin-induced dilation of pial arterioles by 47%. After concurrent 90 mg/kg i.v. ASA plus 300 microM ASA topically applied to the brain, stimulated increases of CSF prostaglandins were reduced by 79%, while bradykinin-induced dilation was reduced by 78%. ASA did not reduce the dilator activity of either acetylcholine or ventilation with 10% O2-9% CO2. Acetylcholine- but not bradykinin-induced dilation was reduced by NG-nitro-L-arginine methyl ester. These results indicate intravenous ASA produced a relatively selective inhibition of cerebral microvascular cyclooxygenase and partial inhibition of bradykinin-induced dilation. Further inhibition of dilation occurred following ASA administered both systemically and topically to the brain. This indicates two sources of cyclooxygenase, endothelial and nonendothelial, mediate the bradykinin-induced dilation of rabbit pial arterioles. Furthermore, systemic doses of ASA do not eliminate brain prostaglandin formation. |
| Databáze: | OpenAIRE |
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