Phosphoinositide metabolism in peripheral axons.
Cyclitols and phosphoinositides. Wells WW, Eisenberg F, eds. New York: Academic Press, Inc., 1978:535-547
Uptake and incorporation of myo-inositol (87898) and phosphate (14265442) into squid and mouse nerve fibers were examined. Tritiated myo-inositol and choline (62497) were used as precursors of the polar headgroups of phosphatidylinositol and phosphatidylcholine. Incubation of squid axoplasm with these precursors and with cytidine-diphosphocholine (987780) yielded more incorporation of myo-inositol than choline into lipid. Autoradiography of mouse sciatic nerve demonstrated that inositol was selectively incorporated into lipid in the axoplasm. The distribution of silver grains over the Schwann cell cytoplasm suggested that both choline and myo-inositol lipid syntheses initially occur in this cell. Some of the lipid formed in Schwann cell cytoplasm was transferred into myelin when incorporation periods were lengthened and some of the phosphatidylinositol formed in the axoplasm was transferred to a region overlaying the axolemma. Inorganic phosphate labeled with 33-P was used to characterize further the axon associated lipid metabolism in mouse myelinated fibers. This precursor was incorporated largely into phosphatidylinositol-bisphosphate and protein. Quantitative examination of electron microscope autoradiographs of cross sectioned fibers revealed sites of incorporation localized to junctions where Schwann cell and axon plasma membranes were located. The authors suggest that phosphatidylinositol and protein are phosphorylated at sites in these membranes.
NIOSH-Grant; Neurotoxic-effects; Phospholipids; Neurophysiology; Peripheral-nervous-system; Cellular-function; Cytological-analysis; Analytical-methods; Metabolic-effects; Laboratory-animals; Research-laboratories
Pathology Albert Einstein Coll of Med 1300 Morris Park Avenue Bronx, N Y 10461
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Cyclitols and phosphoinositides
Yeshiva University, New York, New York