Regional changes of membrane phospholipid concentrations in rabbit spinal cord following brief repeated ischemic insults

Changes in the concentration of membrane-bound phospholipids following sing le (25-min) spinal cord ischemia and 3 h of reperfusion were determined. Th ese were compared with the changes following brief repeated (8-, 8-, and 9- min) ischemia followed each time by reperfusion for 1 h, or the same period s of ischemia followed by 8 h, 8 h, and 24 h of reperfusion, respectively. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and sphingomyelin (SM) were assayed in re gions of the spinal cord of the rabbit, including gray matter, white matter , dorsal horns, intermediate zone, and ventral horns. The brief repeated is chemia with l-h reperfusions produced more extensive degradation of phospho lipids in almost all regions compared with the equivalent; time of ischemia (25 min) in a single period. After a lengthy reperfusion after repeated is chemia, the phospholipids were resynthesized with the exception of the phos phatidylinositol in the gray matter. The resynthesis was most pronounced in the dorsal horns and in the white matter.