Age dependent accumulation of N-acyl-ethanolamine phospholipids in ischemic rat brain: a P-31 NMR and enzyme activity study

N-acyl-ethanolamine phospholipids (NAPE) can be formed as a stress response during neuronal injury; and they are precursors for N-acyl-ethanolamines ( NAE), some of which are endocannabinoids. The levels of NAPE accumulated du ring post-decapitative ischemia (6 h at 37 degrees C) were studied in rat b rains of various age (1, 6, 12, 19, 30, and similar to 70 days) by the use of P-31 NMR spectroscopy of lipid extracts. This ability to accumulate NAPE was compared with the activity of N-acyltransferase and of NAPE-hydrolyzin g phospholipase D (NAPE-PLD) in brain microsomes. These two enzymes are inv olved in the formation and degradation of NAPE, respectively. The results s helved that 1) the ability to accumulate NAPE during post-decapitative isch emia is especially high in the youngest rats and is markedly reduced in old er brains [in 1-day-old rat brains NAPE accumulated to 1.5% of total phosph olipids, while in 30-day-old rat brains NAPE accumulation could not be dete cted (detection limit 0.09 %)]; and 2) this age pattern of accumulation can be explained by a combination of the decreased activity of N-acyltransfera se and the increased activity of NAPE-PLD during development. These results point out that it would be advantageous to investigate a potential cytopro tective role of NAPE in the brains of very young rats.