Decomposition of Phospholipids During Wallerian Degeneration J. Domonkos

Abstract

—Of the lipid metabolic changes in Wallerian degeneration, the decomposition of phosphatides was studied in the early stages, 2–14 days after the nerve had been cut. It was found that the decomposition of phosphatides begins only 6 days after section. The amounts of lipid‐P and fatty acid ester decrease in parallel. However, a greatcr decrease in the amount of fatty aldehyde was observed than of the lipid‐P and fatty acid ester; this indicates that the vinyl ether bonds of glycerophosphatides are more sensitive to the degenerative process than the fatty acid ester or phosphorus. The fatty acid ester: lipid‐P ratio, calculated from the results, does not change; however, the fatty aldehyde: lipid‐P ratio shows a marked decrease during this same period. The values of the ratios indicate that in the 2nd week following nerve section, decomposition of glycerophosphatides containing fatty aldehyde (i.e. plasmalogens), in contrast to glycerophosphatides of diacyl form, may be only partial. Thus, in the 2nd week of Wallerian degeneration the formation of lysophosphatides may be presumed to come from the plasmalogens.

Myelin

“…Lipolytic enzymes undoubtedly contribute to the degradative process. An increase in Iysolecithin in transected cat nerve was reported by Berryet al (1965), while Domonkos and Heiner (1968) found an increase in Iyso "cephalin." Webster (1973) observed substantial increases of phospholipases Al and A 2 in rat sciatic nerve beginning as early as 2 days after section and rising to 8 times normal values by the 2nd week.…”

Myelin

“…There is evidence that lipolytic enzymes may contribute to the process of myelin degradation. An increase in lysolecithin in transected cat nerve has been reported by Berry et al (1965), while Domonkas and Heiner ( 1968) found an increase in lyso-"cephalin," presumably lysoethanolamine plasmalogen. Webster ( 1973) observed substantial increases of phospholipases A1 and A2 in rat sciatic nerve beginning as early as 2 days after section and rising to eight times normal values by the second week, and suggested that lysophosphatides may be active as solubilizing agents in the demyelination process.…”

Peripheral Nerve Phospholipid Composition: Development in Normal Nerve and Age‐Dependent Changes in Wallerian Degenerated Nerve

“…Determinations of the phospholipid composition of peripheral nerve undergoing Wallerian degeneration secondary to nerve transection (Brante, 1949;Johnson et al, 1949a,b;McCaman and Robins, 1959;Berry et al, 1965;Domonkos and Heiner, 1968;Wood and Dawson, 1974) and secondary to nerve crush (Burt et al, 1950) have also been limited to adult material. Despite great differences in the methods used by these investigators to quantitate individual phospholipid subclasses, a consistent literature finding during Wallerian degeneration of adult peripheral nerve is a temporal pattern Characterized by less rapid and less complete absolute loss of PC relative to that of nerve lipid in general and other phospholipid subclasses in particular.…”