The movement of N-arachidonoylethanolamine (anandamide) across cellular membranes

This review presents and explores the hypothesis that N-arachidonoylethanol amine (AEA, also called anandamide) is transported across cellular membrane s by a process that is protein-mediated. Support for this hypothesis comes from experiments demonstrating that cellular accumulation of extracellularl y applied AEA is saturable, time and temperature dependent and exhibits sel ective inhibition by various structural analogs of AEA. The accumulation of AEA is cell specific; data is presented demonstrating that several cell ty pes, including the bovine adrenal zona glomerulosa cell, exhibit very high capacity for AEA accumulation while others, such as the HeLa cell, have a v ery low capacity. The transport process has the characteristics of facilita ted diffusion; it is bi-directional, not dependent on either ATP or extrace llular sodium and exhibits the trans effect of flux coupling. Several impor tant questions remain to be answered regarding the carrier, including its m olecular structure and its role in the release and inactivation of endogeno usly produced AEA. (C) 2000 Elsevier Science Ireland Ltd. All rights reserv ed.