Phospholipase a Activities in Normal and Sectioned Rat Sciatic Nerve

Abstract

Abstract— The phospholipase A1 (EC 3.1.1.32) and A2 (EC 3.1.1.4) activities of rat sciatic nerve homogenates have been studied. With phosphatidylcholine as substrate normal nerve had significant activity of both types at pH 5.0. Substantial increases occurred in nerve undergoing Wallerian degeneration after transection, beginning as early as 2 days after operation and rising to eight times normal values by the second week.

Occurrence of phospholipase A1–A2 and lysophosphatidylcholine acyltransferase activities in axolemma‐enriched fractions of brain stem, optic pathway, and cranio‐spinal nerves of the rabbit

“…Significant phospholipase A, and A2 activities, at pH 5.0 in the homogenate of rat whole sciatic nerve have also been reported by Webster [1973], who suggested that both types of enzyme were associated, at least in part, with Schwann cells.…”

Myelin

“…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. He suggested that Iysophosphatides may be active as solubilizing agents.…”

“…On the other hand, Schwann cells destined to form myelin internodes continue to divide, transferring axons to their progeny after each division until they invest a single axon. When the diameter of the single axon reaches 1-2 J.Lm, PNS myelination is ready to commence (Peters and Vaughn, 1970;Webster, 1971;Martin and Webster, 1973;Webster et al, 1973).…”

Myelin

“…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.…”

“…On the other hand, Schwann cells destined to form myelin internodes continue to divide, transferr:ng axons to their progeny after each division until they invest a single axon with a diameter of about 2 p.m. Under such circumstances, PNS myelination is ready to commence (Peters and Vaughn, 1970;Webster, 1971;Martin and Webster, 1973;Webster et al, 1973).…”