Cannabinomimetic behavioral effects of and adenylate cyclase inhibition by two new endogenous anandamides

• Published in: European journal of pharmacology 1995-12, Vol.287 (2), p.145-152
• Main Authors: Barg, Jacob, Fride, Ester, Hanus, Lumir, Levy, Rivka, Matus-Leibovitch, Noa, Heldman, Eliahu, Bayewitch, Michael, Mechoulam, Raphael, Vogel, Zvi
• Format: Article
• Language: English
• Subjects: Adenylate cyclase; Adenylyl Cyclases - drug effects; Anandamide; Animals; Arachidonic Acids - pharmacology; Binding, Competitive; Biological and medical sciences; Cannabinoid receptor; Cannabinoids - pharmacology; Cells, Cultured - drug effects; Dose-Response Relationship, Drug; Endocannabinoids; Enzyme Inhibitors - pharmacology; Female; GTP-binding protein; Medical sciences; Mice; Mice, Inbred C57BL; Neuropharmacology; Neurotransmitters. Neurotransmission. Receptors; Peptidergic system (neuropeptide, opioid peptide, opiates...). Adenosinergic and purinergic systems; Pharmacology. Drug treatments; Polyunsaturated Alkamides; Receptors, Cannabinoid; Receptors, Drug - drug effects
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/0014-2999(95)00487-4

We have previously shown that the endogenous putative cannabinoid ligand arachidonylethanolamide (anandamide, 20:4, n − 6) induces in vivo and in vitro effects typical of a cannabinoid agonist. We now report that two other endogenous anandamides, docosatetraenylethanolamide (anandamide, 22:4, n − 6) and homo-γ-linolenylethanolamide (anandamide, 20:3, n − 6), have similar activities. The new anandamides bind to SV40-transformed African green monkey kidney cells transfected with the rat brain cannabinoid receptor cDNA and display K I values of 253.4 ± 41.1 and 244.8 ± 38.7, respectively. The value found for arachidonylethanolamide was 155.1 ± 13.8 nM. In addition, the new anandamides inhibit prostaglandin E 1-stimulated adenylate cyclase activity in Chinese hamster ovary-K 1 cells transfected with the cannabinoid receptor, as well as in N 18TG 2 mouse neuroblastoma cells that express the cannabinoid receptor naturally. The IC 50 values for the inhibition of adenylate cyclase in transfected Chinese hamster ovary-K 1 cells were 116.8 ± 8.7 and 109.3 ± 8.6 nM for docosatetraenylethanolamide and homo-γ-linolenylethanolamide, respectively. These values were similar to that obtained with arachidonylethanolamide (100.5 ± 7.7 nM), but were significantly higher than the IC 50 value observed with the plant cannabinoid Δ 9-tetrahydrocannabinol (9.2 ± 8.6 nM). The inhibitory effects of the anandamides on adenylate cyclase activity were blocked by pertussis toxin, indicating the involvement of pertussis toxin-sensitive GTP-binding protein(s). In a tetrad of behavioral assays for cannabinoid-like effects, the two new anandamides exerted similar behavioral effects to those observed with Δ 9-tetrahydrocannabinol and arachidonylethanolamide: inhibition of motor activity in an open field, hypothermia, catalepsy on a ring, and analgesia on a hot plate.