Analysis of reponses in the pulmonary vascular bed of the intact chest rat

Hyman A., Hao Q., Tower A., Kadowitz P., Champion H., Gumusel B., ...More

FASEB Journal, vol.12, no.5, 1998 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 12 Issue: 5
  • Publication Date: 1998
  • Journal Name: FASEB Journal
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Lokman Hekim University Affiliated: No


A new cardiac catheterization technique was used to investigate pulmonary pressure-blood flow relationships in intact spontaneously breathing rats (ISBR) under physiologic conditions with constant left atrial pressure and controlled blood flow within the normal range. The pressure-flow curves in vivo were curvilinear with pulmonary arterial pressure increasing more rapidly at low pulmonary blood flows of 4-8 ml/min, and less rapidly at higher flow rates. Pressure-flow curves were reproducible, and were not altered by 1-1.5 hr period of arrested perfusion, cyclooxygenase blockade, or perfusion with aortic or mixed venous blood. In the intact animal, NG-nitro L-arginine methyl-ester (L-NAME) increased pulmonary arterial pressure at all but the lowest flow rates with a slight effect on the curvilinear pressure-flow relationship. L-NAME attenuated pulmonary vasodilator responses to acetylcholine, bradykinin, adrenomedullin-(13-52) and enhanced the pulmonary vasodilator response to nitroglycerin. The present data suggest that actively-induced pulmonary hypertension is under greater control by endothelium-derived-relaxing factor (EDRF). Results in ISBR demonstrate the pulmonary vasodilator response to adrenomedullin-(13-52) is not mediated by calcitonin gene-related peptide (CGRP) receptors which are not coupled to the release of EDRF and that EDRF may play a role in the regulation of vascular tone at high flow rates. These results indicate that this new technique may provide a useful model for the study of the pulmonary circulation in the intact-chest rat.