Responses of Small Intrapulmonary Arteries to Vasoactive Compounds in the Fetal and Neonatal Lamb: Norepinephrine, Epinephrine, Serotonin, and Potassium Chloride

Abstract

ABSTRACT: Despite considerable study, the mechanisms responsible for the transition of the pulmonary circulation from the fetal to newborn life remain obscure. We compared the responses of third and fourth generation pulmonary arteries to norepinephrine, epinephrine, serotonin, and KC1 from lambs 7 d preterm and 1, 7, and 21 d of age to assess differences between age and third and fourth generations of the pulmonary arterial tree during the transitional period. Preterm vessels were significantly smaller in internal diameter than all other aged vessels for both generations. Fourth generation vessel response to KC1 increased with age (94 ± 1 5 mg/mm2, preterm; 259 ± 3 1 mg/mm2, 21 d). Third generation vessel response to KC1 did not change with age (135 ± 15 mg/mm2, preterm; 158 ± 1 8 mg/mm2, 21 d). There were no differences in maximum response to norepinephrine and epinephrine between ages; however, third generation vessel response to these compounds was significantly greater (30-60% of maximum KC1 response) than fourth generation vessel response (0- 10%). Third and fourth generation vessels had the same maximum response to serotonin regardless of age or generation. Third generation vessels were significantly reduced in sensitivity (log molar concentration which produced 50% of the maximum response—EC5o) to norepinephrine at d 1 (5.89 ± 0.12 log molar) and 7 (5.90 ± 0.21) compared to preterm (6.48 ± 0.10) and 21 d of age (6.50 ± .03). Both third and fourth generation vessels were less sensitive to serotonin at d 1 (5.04 ± 0.17, third; 5.61 ± 0.10, fourth) compared to d 7 (5.77 ± 0.13, third; 6.36 ± 0.12, fourth) and 21 d (5.82 ± 0.24, third; 6.50 ± 0.15, fourth). A similar nonsignificant trend occurred in third generation vessels to epinephrine at d 1 and 7 compared to vessels at preterm and 21 d of age. Greater than 75% of fourth generation vessels did not respond to norepinephrine and epinephrine. The small intrapulmonary arteries of the neonate are undergoing dynamic changes in physiologic response which are dependent upon age and generation

DOI: 10.1203/00006450-198904000-00009

Statistics

050100150'95'97'99'01'03'05'07'09'11'13'15'17
Citations per Year

365 Citations

Semantic Scholar estimates that this publication has 365 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Dunn1989ResponsesOS, title={Responses of Small Intrapulmonary Arteries to Vasoactive Compounds in the Fetal and Neonatal Lamb: Norepinephrine, Epinephrine, Serotonin, and Potassium Chloride}, author={Julie A Dunn and Vichien Lorch and Sachchida N Sinha}, journal={Pediatric Research}, year={1989}, volume={25}, pages={360-363} }