Fatty acid composition and dynamics of phospholipids from fresh water fish Prochilodus lineatus brain and spinal cord.

The phospholipid and fatty acid composition of the brain and spinal cord lipids of fresh water fish Prochilodus lineatus ("sábalo") were studied. The fluorescence anisotropy of phospholipids labelled with 1.6-diphenyl 1.3.5-hexatriene, was also investigated. Phosphatidyl-choline was the most abundant phospholipid followed by phosphatidyl-ethanolamine, phosphatidyl-serine, phosphatidyl-inositol and sphingomyelin. The fatty acid composition of all phospholipids except sphingomyelin showed the presence of n-9, n-6 and n-3 series of unsaturated acids. The presence of n-6 polyunsaturated fatty acid was represented by arachidonic acid that was found preferentially in phosphatidyl-inositol. N-3 fatty acids were represented by 20:5n-3, 22:5n-3 and 22:6n-3. Docosa 4,7,10,13,16,19 hexaenoic acid was the most abundant of n-3 fatty acids and was preferentially found in phosphatidyl ethanolamine and phosphatidyl-serine. The percentage of 22:6n-3 acid decreased with age. The simultaneous presence of n-6 fatty acids (arachidonic acid) and n-3 fatty acids in fresh water fishes contrast with the absence of n-6 fatty acids in nervous tissue of marine fishes. Phosphatidyl choline was the most fluid of all phospholipids from brain and spinal cord.