Cold resistance of the brain during hibernation. III. Evidence of a lipid adaptation.

The composition of membrane-bound lipids of brain from both warm-adapted and hibernating hamsters were different in the complex lipid fraction as well as their fatty acyl chains. During hibernation the content of cholesterol was less, but there were greater amounts of both the phosphatidylcholines and phosphatidylethanolamines. There were small but significant increases in monounsaturated fatty acids as well as arachidonic acid in all the glycerophosphatides of the hibernating hamster, whereas a decrease in isomyristic acid was o0served in the sphingomyelins. The most significant changes observed occurred in the fatty aldehyde composition of ethanolamine plasmalogen. A dramatic increase in oleyaldehyde was observed during hibernation. These changes in membrane-bound lipids may account for the cold-resistant properties of the brain during hibernation by retaining the fluid nature of the cell membrane.