Production and metabolism of platelet-activating factor in the normal and ischemic fetal rat brain.

Production and metabolism of platelet-activating factor (PAF) in the fetal rat brain under normal and under ischemic stress conditions were examined. Endogenous PAF levels, determined by a bioassay using PAF-stimulated platelet release of [3H]serotonin, averaged 2.32 +/- 2.

Transient rise of glucose uptake in the fetal rat brain after brief episodes of intrauterine ischemia.

In a rat model of intrauterine growth retardation and fetal brain ischemia, the maternal-fetal circulation was obstructed for up to 40 min in 20-day gestational age rats by occluding (restriction) the uterine blood vessels supplying the placenta. After restriction, flow was returned (reperfusion) for designated times. A time-dependent depletion of cerebral pyruvate levels (from 0.

Gangliosides stimulate synthesis of prostaglandin E2 and prostacyclin in fetal rat brain hemispheres after episodes of global intrauterine ischemia.

The ability of brain preparations from 20-day-old rat fetuses to synthesize prostanoids in vitro before and after interruption of the maternal-fetal blood flow was examined using a radioimmunoassay technique. Synthesis of thromboxane B2 (TxB; the stable thromboxane A2 metabolite) decreased with increasing restriction time; conversely, it was elevated with reperfusion. Synthesis of 6-keto prostaglandin F1 alpha (PGF; the stable prostacyclin metabolite) and prostaglandin E2 (PGE) prostanoids remained unchanged after 20 min restriction and through a 2 hr reperfusion period.

Platelet-activating factor stimulates arachidonic acid release and enhances thromboxane B2 production in intact fetal rat brain ex vivo.

The ability of brain preparations from 20-day-old rat fetuses to synthesize eicosanoids in the presence of platelet activating factor (PAF) was investigated. A rise (49%) in thromboxane B2 (TxB2; the stable thromboxane A2 metabolite) was observed after 30 min in the presence of 0.6 microM PAF.

Generation of arachidonic acid and diacylglycerol second messengers from polyphosphoinositides in ischemic fetal brain.

Intracerebral administration of [3H]arachidonic acid ([3H]ArA) into 19-20-day-old rat embryos, resulted in a rapid incorporation of label into brain lipids. One hour after injection, 55.6 +/- 8.