Effect of Maturation on Endothelium-Dependent Relaxation in Pulmonary Arteries of the Newborn Rabbit.
- Author:
Bong Hee SEO
1
;
So Hyun LEE
;
Kook In PARK
;
Moon Sung PARK
;
Chul LEE
;
Dong Gwan HAN
Author Information
1. Department of Pediatrics, College of Medicine, Yonsei University, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Endothelium-derived relaxing factor (EDRF);
Pulmonary artery;
Newborn rabbit
- MeSH:
Acetylcholine;
Endothelium;
Endothelium-Dependent Relaxing Factors;
Histamine;
Humans;
Indomethacin;
Infant, Newborn*;
Nitroprusside;
Pulmonary Artery*;
Rabbits;
Relaxation*
- From:Journal of the Korean Society of Neonatology
2001;8(2):247-256
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: This study was done to determine whether maturatin alters endothelium- dependent responses in pulmonary arteries. METHODS: Vascular rings of pulmonary arteries, with and without endothelium, taken from rabbits of 3 and 30 days of age were suspended in organ chambers filled with Krebs-Henseleit solution, bubbled with 95% O2-5% CO2 and maintained at 37degrees C. Immediately after mounting, the rings were stretched progressively until a maximal response to KCl was achieved. The rings were incubated with indomethacin and allowed to equilibrate before contraction and relaxation study. RESULTS: When the endothelium was intact in arterial rings from 3-day-old rabbits, acetylcholine (ACH) (10-6 M) relaxed preconstricted rings with histamine (5x10-6 M) (98.1 4.7% relaxation, mean SD). In rings without endothelium, KCl (10-2 to 9x10-2 M) and histamine (5x10-8 to 10-5 M) caused concentration-dependent contractions. When normalized to maximal contractions achieved to each agonist, the concentration-effect curves to KCl and histamine in rings without endothelium were similar to both ages. Rings with endothelium showed a progressive shift to the right of the concentration- effect curve to histamine. Relaxation to sodium nitroprusside were unaffected by age. In preconstricted ring, ACH (10-8 to 5x10-6 M) caused relaxations in rings with endothelium which were greater at 30-day compared to 3-day-old rabbits. CONCLUSION: These study demonstrates that endothelium-dependent relaxation increase with age, possibly due to changes in the release and/or effect of endothelium-derived relaxing factor (EDRF or nitric oxide) from pulmonary arteries during the neonatal period.
