Agents that modify EDRF formation alter antiplatelet properties of brain arteriolar endothelium in vivo
| Autor: | W. I. Rosenblum, G. H. Nelson, H. Nishimura, S Boynton |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Blood Platelets
Male Platelet Aggregation Endothelium Physiology Administration Topical Pharmacology Arginine Nitric Oxide Mice chemistry.chemical_compound In vivo Physiology (medical) medicine Animals Platelet Evans Blue Mice Inbred ICR omega-N-Methylarginine Arginase Endothelium-derived relaxing factor Anatomy Acetylcholine Arterioles medicine.anatomical_structure chemistry Cerebrovascular Circulation Injections Intravenous Omega-N-Methylarginine Endothelium Vascular Cardiology and Cardiovascular Medicine Platelet Aggregation Inhibitors Ex vivo |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 261:H15-H21 |
| ISSN: | 1522-1539 0363-6135 |
| Popis: | In the presence of circulating Evans blue a helium-neon laser injures the endothelium of brain surface arterioles in situ. The injury is known to selectively eliminate endothelium-dependent responses. The present study documents in mice the fact that such endothelial sites become selectively attractive to passing platelets that have been activated as a result of more severe injury upstream. We then test the hypothesis that the “capture” of platelets at the downstream site is due to loss of “classical” endothelial-dependent relaxing factor of acetylcholine (EDRFACh) at that site. EDRFACh is known to inhibit platelet adhesion/aggregation and is synthesized from L-arginine. We show that agents that would either enhance or reduce the synthesis of local EDRFACh reduce or increase the incidence of capture as predicted by the hypothesis. Thus NG-monomethyl-L-arginine (L-NMMA) and arginase that would reduce synthesis of EDRFACh enhanced platelet capture. L-Arginine, which would enhance synthesis of EDRFACh, inhibited platelet capture. In addition, L-NMMA and arginase enhanced platelet aggregation over the more severely damaged site upstream from the site of capture. Ex vivo studies of platelets harvested from treated mice showed that the platelets themselves were unaffected by the treatments that, except for arginase given intravenously, all involved topical application of the tested drugs. |
| Databáze: | OpenAIRE |
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