PROSTAGLANDIN SYNTHESIS AND EDEMA FORMATION DURING REPERFUSION FOLLOWING EXPERIMENTAL BRAIN ISCHEMIA IN THE GERBIL

Regional brain tissue prostaglandin (PG) levels were measured during ischemia produced by bilateral carotid occlusion for 1 h and following restoration of flow. In the normal gerbil, the frontal cortical levels of PGF2.alpha. were 6.7 .+-. 1.3 pg/mg and, for PGE2, 6.4 .+-. 1.1 pg/mg of brain tissue protein. Following 1 h of ischemia PGF2.alpha. rose to 50.4 .+-. 8.3 pg/mg whilst there was only a slight rise in PGE2 (10.7 .+-. 1.6 pg/mg). Post ischemic values for parietal and occipital area were somewhat higher, but showed the same trend. Within 15 min of the restoration of flow there was a massive increase in PGF2.alpha. levels which reached a peak at 2 h (300 pg/mg) and then subsided to control values. PGE2 levels did not change for the first 30 min of recirculation, but then rose for the rest of the period of observation. The pattern of cytotoxic edema resembled PGF2.alpha. closely while the Evans blue staining (vasogenic edema) was similar in time to the PGE2 pattern.