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N-Arachidonoylethanolamine (anandamide, AEA) is a putative endogenous ligand of the cannabinoid receptor. Intact cerebellar granule neurons in primary culture rapidly accumulate AEA. [3H]AEA accumulation by cerebellar granule cells is dependent on incubation time (t1/2 of 2.6 /- 0.8 min at 37[degrees]C) and temperature. The accumulation of AEA is saturable and has an apparent Km of 41 /- 15 [mu]M and a Vmax of 0.61 /- 0.04 nmol/min/106 cells. [3H]AEA accumulation by cerebellar granule cells is significantly reduced by 200 [mu]M phloretin (57.4 /- 4% of control) in a noncompetitive manner. [3H]AEA accumulation is not inhibited by either ouabain or removal of extracellular sodium. [3H]AEA accumulation is fairly selective for AEA among other naturally occurring N-acylethanolamines; only N-oleoylethanolamine significantly inhibited [3H]AEA accumulation at a concentration of 10 [mu]M. The ethanolamides of palmitic acid and linolenic acid were inactive at 10 [mu]M. N-Arachidonoylbenzylamine and N-arachidonoylpropylamine, but not arachidonic acid, 15-hydroxy-AEA, or 12-hydroxy-AEA, compete for AEA accumulation. When cells are preloaded with [3H]AEA, temperature-dependent efflux occurs with a half-life of 1.9 /- 1.0 min. Phloretin does not inhibit [3H]AEA efflux from cells. These results suggest that AEA is accumulated by cerebellar granule cells by a protein-mediated transport process that has the characteristics of facilitated diffusion.

(C) 1997 International Society for Neurochemistry