Selective Ligands and Cellular Effectors of a G Protein-Coupled Endothelial Cannabinoid Receptor
作者:László Offertáler、Fong-Ming Mo、Sándor Bátkai、Jie Liu、Malcolm Begg、Raj K. Razdan、Billy R. Martin、Richard D. Bukoski、George Kunos
DOI:10.1124/mol.63.3.699
日期:2003.3.1
The cannabinoid analog abnormal cannabidiol [abn-cbd; (−)-4-(3–3,4- trans - p -menthadien-[1,8]-yl)-olivetol] does not bind to CB1 or CB2 receptors, yet it acts as a full agonist in relaxing rat isolated mesenteric artery segments. Vasorelaxation by abn-cbd is endothelium-dependent, pertussis toxin-sensitive, and is inhibited by the BKCa channel inhibitor charybdotoxin, but not by the nitric-oxide synthase inhibitor N ω-nitro-l-arginine methyl ester or by the vanilloid VR1 receptor antagonist capsazepine. The cannabidiol analog O-1918 does not bind to CB1 or CB2 receptors and does not cause vasorelaxation at concentrations up to 30 μM, but it does cause concentration-dependent (1–30 μM) inhibition of the vasorelaxant effects of abn-cbd and anandamide. In anesthetized mice, O-1918 dose-dependently inhibits the hypotensive effect of abn-cbd but not the hypotensive effect of the CB1 receptor agonist (−)-11-OH-Δ9-tetrahydrocannabinol dimethylheptyl. In human umbilical vein endothelial cells, abn-cbd induces phosphorylation of p42/44 mitogen-activated protein kinase and protein kinase B/Akt, which is inhibited by O-1918, by pertussis toxin or by phosphatidylinositol 3 (PI3) kinase inhibitors. These findings indicate that abn-cbd is a selective agonist and that O-1918 is a selective, silent antagonist of an endothelial “anandamide receptor”, which is distinct from CB1 or CB2 receptors and is coupled through Gi/Go to the PI3 kinase/Akt signaling pathway.
大麻素类似物异常大麻二酚[abn-cbd;(-)-4-(3-3,4-trans-p-menthadien-[1,8]-yl)-olivetol]不与 CB1 或 CB2 受体结合,但它在松弛大鼠离体肠系膜动脉节段方面起着完全激动剂的作用。abn-cbd 的血管舒张作用是内皮依赖性的,对百日咳毒素敏感,会受到 BKCa 通道抑制剂 charybdotoxin 的抑制,但不会受到一氧化氮合成酶抑制剂 N ω-硝基-精氨酸甲酯或香兰素 VR1 受体拮抗剂 capsazepine 的抑制。大麻二酚类似物 O-1918 不与 CB1 或 CB2 受体结合,在高达 30 μM 的浓度下不会导致血管舒张,但它会导致浓度依赖性(1-30 μM)抑制 abn-cbd 和安乃近的血管舒张作用。在麻醉小鼠中,O-1918 可剂量依赖性地抑制γ-苄基大麻酚的降压作用,但不能抑制 CB1 受体激动剂(-)-11-OH-Δ9-四氢大麻酚二甲基庚基的降压作用。在人脐静脉内皮细胞中,γ-苄氧羰基大麻酚能诱导 p42/44 丝裂原活化蛋白激酶和蛋白激酶 B/Akt 磷酸化,O-1918、百日咳毒素或磷脂酰肌醇 3(PI3)激酶抑制剂都能抑制这种磷酸化。这些研究结果表明,abon-cbd 是一种选择性激动剂,而 O-1918 则是内皮 "anandamide 受体 "的一种选择性无声拮抗剂,这种受体不同于 CB1 或 CB2 受体,通过 Gi/Go 与 PI3 激酶/Akt 信号通路耦合。