AJP - Heart and Circulatory Physiology, Vol 246, Issue 3 466-H471, Copyright © 1984 by American Physiological Society
Effect of platelet-activating factor on coronary circulation of the domestic pig
G. Feuerstein, L. M. Boyd, D. Ezra and R. E. Goldstein
The platelet-activating factor released by white blood cells and platelets
has been shown to be 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine
(AGEPC). To fully understand the cardiovascular actions of this substance,
we examined the effects of AGEPC on coronary blood flow (CBF) and other
hemodynamic parameters in anesthetized open-chest domestic pigs. Mean
arterial blood pressure (MBP), electrocardiogram, heart rate (HR), left
ventricular pressure, and CBF were continuously recorded. AGEPC was
injected (bolus, 0.1 ml) into the left anterior descending coronary artery
at increasing doses of 0.03-10 nmol. Intracoronary AGEPC produced biphasic
changes in CBF: a dose-dependent increase in CBF (up to 50%) followed by a
decrease (up to 92%) in CBF. The changes in CBF were not directly related
to any systemic effect, although MBP was reduced consistently after a dose
higher than 1 nmol of AGEPC. The increase in CBF produced by AGEPC was not
affected by pretreatment with indomethacin (6 mg/kg) or FPL 55712 (1 or 3
mg), an inhibitor of slow-reacting substance of anaphylaxis (SRS-A). The
decrease in CBF produced by AGEPC was attenuated by FPL 55712 and blocked
by indomethacin. These data suggest that AGEPC release from aggregating
platelets might play a major role in modulating CBF and cardiac function in
states involving platelet-coronary interaction.
