Related Experiment Videos
Sustained effects of platelet-activating factor infusion in piglets
J J Stambouly1, L M Bradley, J F Czaja
1Department of Anesthesiology (Critical Care Medicine), Children's National Medical Center, Washington, District of Columbia 20010.
Pediatric Research
|September 1, 1991
Summary
Platelet-activating factor (PAF) causes severe pulmonary vasoconstriction in piglets. PAF receptor blockade effectively treats this condition, but not hypoxia-induced vasoconstriction, suggesting distinct mechanisms.
Area of Science:
- Cardiovascular Physiology
- Neonatal Medicine
- Pharmacology
Background:
- Platelet-activating factor (PAF) is known to induce pulmonary vasoconstriction (PV).
- Tachyphylaxis can limit the effects of PAF.
- Neonatal diseases may involve PAF-mediated PV.
Purpose of the Study:
- To investigate the effects of PAF exposure on pulmonary hemodynamics in neonatal piglets.
- To compare the effects of PAF with acute hypoxia.
- To evaluate the efficacy of PAF receptor blockade in mitigating PAF-induced PV.
Main Methods:
- Neonatal piglets underwent infusions of PAF (0.05-0.15 nmol/kg/min for 30-180 min).
- Pulmonary and systemic arterial pressures, cardiac index, and ventricular function were measured.
- Selective PAF receptor blockers (SRI 63,441 or WEB 2086) or vehicle were administered.
- Hypoxia was induced (33 +/- 1 mm Hg) for comparison.
Main Results:
- PAF infusion significantly increased mean pulmonary arterial pressure and pulmonary vascular resistance index.
- Acute hypoxia similarly elevated these parameters.
- SRI 63,441 prevented PAF-induced PV but did not affect the hypoxic response.
- PAF receptor blockers rapidly reversed established PAF-induced PV.
Conclusions:
- PAF induces severe and sustained pulmonary vasoconstriction in vivo.
- PAF receptor blockade is a potential therapeutic strategy for neonatal diseases involving PAF-mediated PV.
- Hypoxia-induced PV likely involves mechanisms independent of PAF receptors.