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Endogenous platelet activating factor does not modulate blood flow and metabolism in normal rat brain
P M Kochanek1, J A Melick, R J Schoettle
1Department of Anesthesiology, University of Pittsburgh, Pennsylvania.
Stroke
|March 1, 1990
Summary
Platelet activating factor (PAF) does not affect normal brain blood flow or oxygen use. Unlike eicosanoids, PAF
Area of Science:
- Neuroscience
- Pharmacology
- Physiology
Background:
- Platelet-activating factor (PAF) and eicosanoids are involved in cerebrovascular responses to ischemia.
- Eicosanoids modulate cerebrovascular tone in normal physiological conditions.
- The role of PAF in modulating cerebrovascular tone under normal conditions is not well understood.
Purpose of the Study:
- To investigate the effect of platelet activating factor receptor blockers on cerebral blood flow and metabolic rate in normal rats.
- To compare the effects of PAF receptor blockers with indomethacin, an eicosanoid synthesis inhibitor.
Main Methods:
- 16 rats were used to study the effects of BN 52021 and WEB 2086 (PAF receptor blockers) and indomethacin.
- Measurements included global cerebral blood flow and cerebral metabolic rate for oxygen.
- Drug dosages: BN 52021 (10 and 30 mg/kg), WEB 2086 (5 mg/kg), and indomethacin (10 mg/kg).
Main Results:
- Neither BN 52021 nor WEB 2086 significantly altered cerebral blood flow or the cerebral metabolic rate for oxygen.
- Indomethacin significantly decreased cerebral blood flow (p < 0.05).
- No treatment affected the cerebral metabolic rate for oxygen compared to baseline.
Conclusions:
- In the normal rat brain, platelet activating factor concentrations are below the threshold to modulate cerebral blood flow or oxygen metabolism.
- Unlike eicosanoids, PAF does not appear to play a significant role in regulating cerebrovascular tone under normal physiological conditions.