DEVELOPMENTAL DIFFERENCES IN ENDOTHELIUM-DEPENDENT RESPONSES IN ISOLATED OVINE PULMONARY-ARTERIES AND VEINS

Citation
Rh. Steinhorn et al., DEVELOPMENTAL DIFFERENCES IN ENDOTHELIUM-DEPENDENT RESPONSES IN ISOLATED OVINE PULMONARY-ARTERIES AND VEINS, The American journal of physiology, 264(6), 1993, pp. 2162-2167
Citations number
32
Categorie Soggetti
Physiology
ISSN journal
00029513
Volume
264
Issue
6
Year of publication
1993
Part
2
Pages
2162 - 2167
Database
ISI
SICI code
0002-9513(1993)264:6<2162:DDIERI>2.0.ZU;2-5
Abstract
Despite evidence for an important role for endothelium-derived relaxin g factor (EDRF) in transitional circulation, previous in vitro studies of newborn pulmonary arteries have demonstrated diminished EDRF activ ity when compared with arteries from older animals. We studied pulmona ry arteries and veins isolated from early newborn and juvenile sheep u sing standard tissue bath techniques. Incubation of vessels with the n itric oxide synthase inhibitor N(omega)-nitro-L-arginine (L-NNA) const ricted veins but not arteries from both age groups. Further studies us ing preconstricted vessels revealed that arteries relaxed to acetylcho line (ACh), with significantly greater responses observed in juvenile arteries. Veins from both age groups contracted to ACh. Pretreatment w ith prostaglandin inhibitors (indomethacin and SQ 29,548) diminished A Ch relaxations in pulmonary arteries from both age groups, greatly enh anced relaxations to ACh in newborn pulmonary veins, and depressed con tractions in juvenile pulmonary veins. Removal of endothelium mechanic ally or functionally with prostaglandin inhibitors and L-NNA eliminate d relaxations to ACh in pulmonary arteries from both age groups and re sulted in contractions in veins. We conclude that isolated pulmonary v eins from newborn sheep exhibit both baseline and stimulated release o f EDRF, and we speculate that these venous responses may be important in the transitional pulmonary circulation.