PHOSPHOLIPIDS IN THE BRAIN AND SERUM OF RATS SUBJECTED TO EXPERIMENTAL MANGANESE TREATMENT
Phospholipids are an essential constituent part of the cells. Ethanolami-ne phosphatine (EP), sphingomyelin (SPM), and to a lesser degree lecithin (L) and serine phosphatide (SP) enter in the myelin composition (16). The metal complexes of phospholipids are mainly concentrated in the cytoplasmic membrane, in the mitochondrial and nuclear fraction. Letithin (phospha-tidylcholine) and phosphatidylethanolamine (70-80 per cent of the total amount of phospholipids) build up the basic mass in
... ipid membranes. The brain membranes contain in addition phosphatidylserine (18), pho-sphatide acid and its polymer polyglycerophosphatide (PGP). Presumably-the permeability of nerve membranes may undergo modification owing to th, ability of inositol-containing phospholipids (monophosphoinositide phose phatide-MPIP) to form stable complexes with Ca 2 + through their monoes-terified P0 4 ~ 3 groups (1, 9). The exceptionally important role played by magnesium phospholipids in accomplishing the numerous nerve cell transformations is well known (11). Manganese whose electron configuration outlines it as a good chelate-producer, may participate in complex compounds with the phospholipids (5), where through Ca 2 + and Mg 2 " f replacement, the biological properties of the compounds will be altered. The latter opinion is confirmed by our studies since we were successful in establishing a reduction of the above ions 1 concentration in the brain and serum of rats under manganese effect. Pyridoxalphosphate (PLP) is a specific co-factor, promoting the activation of sphingomyelin synthesis in the brain (3, 17), whereas manganese exerts effect on the PLP content. We found a reduction of the latter in the brain, liver and blood of animals treated with manganese (5). The above findings gave us sufficient reason to surmise the occurrence of derangements in fat metabolism, respectively, in the concentration of pho spholipids under the effect of manganese. Material and Methods The study was conducted on 80 fully mature male white rats, weighing 130± 15 g in the average, and distributed in groups as shown in Table 1. Serum phospholipids were demonstrated using the tests of Hanry, and in 10 per cent homogenate-according to the method of McMurray (14) as modified by Smirnov and co-authors (2) and Karagezyan (10). The staining of dots was carried out with iodine vapours (15). Phospholipids in the brain were calculated as lipidic P in mcg/g fresh tissue, and in the serum-in mg% phosphatides, resp. P.