DOCOSAHEXAENOIC ACID DECREASES PHOSPHOLIPASE A(2) ACTIVITY IN THE NEURITES NERVE GROWTH CONES OF PC12 CELLS/

Docosahexaenoic acid (DHA) accumulates in nerve growth cones (NGC) dur ing perinatal development and it is neuroprotective in ischemia. Becau se the phospholipases A(2) (PLA(2)) are present in NGC and these enzym es function in both ischemia and longterm potentiation, the relationsh ip between DHA and PLA(2) was investigated in the NGC of nerve growth factor-differentiate PC12 cells. When PC12 cells were incubated with [ H-3]DHA, it primarily esterified in ethanolamine glycerolipids and con centrated initially in cell bodies with similar levels present in the neurite/nerve growth cone (N/NGC) fraction after 4 days. PLA(2) activi ty in the N/NGC fraction was investigated using [C-14]arachidonic acid -labeled phosphatidylinositol ([C-14-AA]PI) as substrate. Heat denatur ation and pharmacological inhibition showed that much of the PLA(2) ac tivity was calcium-independent and secretory rather than cytosolic. Su pplementing the media with as little as 33 nM DHA significantly reduce d PLA(2) activity in the N/NGC fraction. J. Neurosci. Res. 54:805-813, 1998. (C) 1998 Wiley-Liss, Inc.