Anandamide (N-arachidonoyl-ethanolamine, AEA) was the first endogenous ligand of cannabinoid receptors to be discovered. Yet, since early studies, AEA appeared to exhibit also some effects that were not mediated by cannabinoid CB 1 or CB 2 receptors. Indeed, AEA exerts some behavioral actions also in mice with genetically disrupted CB 1 receptors, whereas in vitro it is usually a partial agonist at these receptors and a weak activator of CB 2 receptors. Nevertheless, several pharmacological effects of AEA are mediated by CB 1 receptors, which, by being coupled to G-proteins, can be seen as AEA 'metabotropic' receptors. Furthermore, at least two different, and as yet uncharacterized, G-protein-coupled AEA receptors have been suggested to exist in the brain and vascular endothelium, respectively. AEA is also capable of directly inhibiting ion currents mediated by L-type Ca 2+ channels and TASK-1K + channels. However, to date the only reasonably well characterized, non-cannabinoid site of action for AEA is the vanilloid receptor type 1 (VR1), a non-selective cation channel gated also by capsaicin, protons and heat. VR1 might be considered as an AEA 'ionotropic' receptor and, under certain conditions, mediates effects ranging from vasodilation, broncho-constriction, smooth muscle tone modulation and nociception to stimulation of hippocampal pair-pulse depression, inhibition of tumor cell growth and induction of apoptosis.
|Number of pages||15|
|Journal||Prostaglandins, Leukotrienes and Essential Fatty Acids|
|Publication status||Published - 2002|
ASJC Scopus subject areas
- Clinical Biochemistry
- Endocrinology, Diabetes and Metabolism