Changes in the Fatty Acyl Composition of Phospholipids in the Optic Tectum and Optic Nerve of Temperature-Acclimated Goldfish

Abstract

The optic tectum and optic nerves of goldfish that were acclimated to 5, 15, and 25 C were examined for their phospholipid composition, and the acyl group composition of the various phospholipid species was determined. The acyl group composition of 1,2-diacyl-sn-glycero-3-phosphoethanolamine (D-GPE) differs distinctly from that of 1-alkenyl-2-acyl-sn-glycero-3-phosphoethanolamine (P-GPE); P-GPE of tectum resembles that of nerve, while D-GPE differs. The acyl group composition of choline glycerophospholipid (CGP) of tectum and nerve differs slightly but significantly. The acyl group composition of serine glycerophospholipid differs from that of D-GPE and CGP and is also different in tectum and nerve. Nerve possesses a higher content of P-GPE than tectum at all three temperatures. The ratio P-GPE/D-GPE + P-GPE increases with a rise in acclimation temperature, while the 1-alkenyl-2-acyl-snglycero-3-phosphocholine (P-GPC)/CGP ratio changes significantly only in nerve. An increase in acclimation temperature results in an increase in the content of saturated fatty acids, while the unsaturation index falls. The acyl group composition of tectum resembles that of synaptosomal fractions, while that of nerve is dissimilar to that of myelin. The findings show that acclimation-to-temperature changes include (1) an alteration in the proportion of plasmalogen, and (2) an alteration in the acyl group composition of all phospholipid species analyzed.