Vasoactivity of the coronary artery of rainbow trout, steelhead trout, and dogfish: lack of support for non-prostanoid endothelium-derived relaxation factors

Publisher Website
Google Scholar
Abstract
This study surveyed and compared vasoactive responses of isolated coronary vessels from steelhead trout (Oncorhynchus mykiss), rainbow trout (also O. mykiss), and spiny dogfish (Squalus acanthias). The purpose of the investigation was twofold: to identify vasoactive controls that were possibly mediated by the vascular endothelium and to highlight the possible consequences on vasoactivity of the coronary lesions known to be present in the main coronary of salmonids but not dogfish. The test substances included acetylcholine, adenosine, adenosine triphosphate, adenosine diphosphate, serotonin, thrombin, bradykinin, prostaglandin F2α, prostaglandin I2, prostaglandin E2, and the fatty acids arachidonic acid, docosahexaenoic acid, and eicosapentaenoic acid. Acetylcholine, adenosine, adenosine triphosphate, adenosine diphosphate and prostaglandin F2αtypically produced contractions. Use of endothelial removal techniques and antagonists failed to reveal any relaxations that might involve the endothelium. Thrombin and bradykinin had no vasoactivity. Serotonin, prostaglandin I2, and prostaglandin E2produced relaxations that were not mediated by the endothelium. The powerful relaxations observed with prostaglandin I2and prostaglandin E2and the powerful contractions observed with prostaglandin F2αsuggest a major role of prostanoids in coronary vasoactivity in fish. These prostanoid-mediated mechanisms, in addition to the previously demonstrated powerful contractions with endothelin-1, point to an important role for the endothelium. No major qualitative or quantitative differences in vasoactivity could be related to differences in coronary lesion severity.