|Zehetgruber M et al.|
Basal and stimulated release of long-acting EDRF by bovine pulmonary arteries
Journal of Clinical and Basic Cardiology 1999; 2 (1): 117-119
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Keywords: Acetylcholin, bradykinin, endothelialer Relaxationsfaktor, Lysophosphaditylcholin, Stickoxid, superfusion, acetylcholine, bradykinin, endothelim-derived relaxing factor, lysophosphatidylcholine, nitric oxide, superfusion
Endothelium-derived relaxing factor (EDRF) is supposed to be identical to nitric oxide (NO). A characteristic of NO is its half-life of 6-50 seconds. We report here bioassay experiments suggesting the presence of a long-acting EDRF. An endothelium intact segment of the main bovine pulmonary artery (generator) and an endothelium deprived artery strip (detector) were seperately perfused with Krebs-Henseleit solution. The effluent of the generator was collected and permitted to stand in an open beaker at 37 °C for periods exceeding five minutes. Following this the collected effluent (CE) perfused the histamine precontracted detector, causing significant relaxation. The same degree of relaxation could be observed after storing CE for 80-120 minutes. After reaching steady state generator effluent (G) was directly superfused over the detector (time delay about two seconds) resulting in a more pronounced relaxation. Addition of pharmacological stimuli of EDRF mediated relaxation augmented, addition of haemoglobin inhibited relaxation as well as by CE and G. Our results show that perfusates from bovine pulmonary arteries contain a material with high degree of stability, being responsible for some part of endothelium mediated relaxation. J Clin Basic Cardiol 1999; 2: 117-9.