title: Endothelin-1 increases the pulmonary microvascular pressure and causes pulmonary edema in salt solution but not blood-perfused rat lungs.
abstract: Endothelin-1 (ET-1) is a potent vasoactive peptide that has been reported to cause lung edema. This study tested if the edemagenic effect of ET-1 is due to preferential venoconstriction and, if so, whether the site of resistance is similar with salt solution (PSS) and more physiologic blood perfusate. ET-1 caused concentration-dependent contraction of pulmonary arterial and venous rings, with an EC50 of 1.3 nM in artery and 0.6 nM in vein (p less than 0.05). In PSS-perfused lungs, 5 nM ET-1 caused a 7.0 +/- 0.8 torr pressor response that was associated with a 5.0 +/- 0.3 torr increase in microvascular pressure and a 530 +/- 20 mg increase in lung weight within 10 min. In contrast, KCl-treated lungs had an equivalent pressor response (7.4 +/- 1.1 torr), yet the microvascular pressure increased by only 2.5 +/- 0.4 torr (p less than 0.05 from ET-1) and the lung weight was unchanged. Meclofenamate did not prevent the effect of ET-1 on microvascular pressure or lung weight. In blood-perfused lungs, ET-1 caused a 7.3 +/- 0.1 torr pressor response but only a 2.0 +/- 0.5 torr increase in microvascular pressure and no increase in lung weight. ET-1 had no effect on permeability either of cultured endothelial cell monolayers or in the pulmonary microvasculature in vivo. We conclude that the edemagenic effect of ET-1 in PSS-perfused lungs is mediated through venoconstriction and an increase in microvascular pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002478:Cells, Cultured; D016232:Endothelins / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009929:Organ Size / Q000187:drug effects; D010477:Perfusion; D011189:Potassium Chloride / Q000494:pharmacology; D011652:Pulmonary Circulation / Q000187:drug effects*; D011654:Pulmonary Edema / Q000139:chemically induced* / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D016232:Endothelins; D011189:Potassium Chloride