Endocannabinoids And The Control Of Cardiovascular Function

内源性大麻素与心血管功能的控制

基本信息

批准号：
7732121
负责人：
GEORGE KUNOS
金额：
$ 96.49万
依托单位：
NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/7732121
关键词：
Affect Affinity Amidohydrolases Animals Antihypertensive Agents Aorta Area Blood Pressure Blood Vessels Brain CNR1 gene CNR2 gene Cannabinoids Cardiac Cardiovascular Physiology Cardiovascular system Cells Chemosensitization Cholesterol Chronic Collaborations Conscious Development Embryo Endocannabinoids Endothelium Endothelium-Dependent Relaxing Factors Enzymes Excision Experimental Models Fatty Acids G-Protein-Coupled Receptors GTP-Binding Proteins Head Heart Hypertrophy Human Hypertension Hypotension Inbred SHR Rats Infusion procedures Ligands Lipids Liver Cirrhosis Marijuana Mediating Mediator of activation protein Membrane Mesenteric Arteries Mesentery Peripheral Pertussis Toxin Physiological Preparation Process Protein Kinase Publications Rattus Relaxation Reporting Role Septic Shock Serine Staging Structure Sympatholytics TRPV1 gene Testing Tissues Vanilloid Vasodilation Vasopressins abn-cbd anandamide cannabinoid receptor enantiomer iberiotoxin in vivo inhibitor/antagonist instrument interest kidney cell neurobehavioral normotensive novel prevent receptor receptor coupling reconstitution response restoration virodhamine

项目摘要

Our earlier studies have indicated that the endothelium-dependent vasodilator effect of the anandamide and of some atypical cannabinoid ligands, such as abnormal cannabidiol (abn-cbd) is mediated by a pertussis toxin-sensitive, G protein-coupled receptor distinct from CB1 or CB2. In collaboration with Mechoulam's group we have earlier identified a novel, endocannabinoid-like brain lipid, arachidonoyl L-serine (ARA-S). Contrary to anandamide, ARA-S has no affinity for CB1, CB2 or vanilloid TRPV1 receptors, and it produces partially endothelium-dependent vasodilation in rat isolated mesenteric artery and aorta preparations. In a more recent study just submitted for publication, we have analyzed the effect of ARA-S on Ca2+-activated K+ currents in human embryonic kidney cells stably transfected with the alpha-subunit of the human, large conductance Ca2+-activated K+ (BKCa) channel (HEK293hSlo cells). ARA-S caused relaxation of isolated, intact and denuded, small mesenteric arteries (pEC50: 5.49 and 5.14, respectively) of the rat. In both preparations the response was inhibited by 100 nM iberiotoxin. In HEK293hSlo cells, ARA-S and its enantiomer N-arachidonoyl-D-serine enhanced the whole cell outward K+ current with similar potency (pEC50: 5.63 and 5.32, respectively). The potentiation was not mediated by ARA-S metabolites, stimulation of known cannabinoid receptors, G proteins, protein kinases or Ca2+-dependent processes, and it was lost after patch excision or following membrane cholesterol depletion, but was restored after cholesterol reconstitution. BKCa currents were also enhanced by anandamide (AEA, pEC50: 5.27) but inhibited by another endocannabinoid, virodhamine (pIC50: 6.35), or by the synthetic cannabinoid O-1918, which blocks ARA-S-induced vasodilation (pIC50: 6.59). These findings indicate that (i) endocannabinoids directly modulate the activity of BKCa channels or a channel-associated component. (ii) This interaction does not involve cytosolic factors but is dependent on the presence of membrane cholesterol (iii) Direct BKCa channel activation likely contributes to the endothelium-independent component of ARA-S-induced mesenteric vasorelaxation. (iv) Depending on the structure of the head group, the effect on BKCa currents is either stimulatory or inhibitory. (v) O-1918 is a potent BKCa channel inhibitor. We have earlier reported that CB1 cannabinoid receptor antagnists, which do not affect blood pressure in healthy, normotensive rats, increase blood pressure as well as cardiac contractile function in 3 different models of experimental hypertension in rats. In contrast, a commercially available inhibitor of fatty acid amidohydrolase (FAAH), the enzyme responsible for the in vivo degradation of the endocannabinoid anandamide normalizes both the elevated blood pressure and the inappropriately high cardiac contractility in hypertensive rats. We have now extended this study by developing our own proprietary FAAH antagonist, which is more potent in producing similar effects both in anesthetized as well as in conscious, chronically instrumented animals. We further verified that these effects are mediated by CB1 receptors, as they can be prevented or acutely reversed by a CB1 receptor antagonist. The hypotensive and negative inotropic effects of the FAAH antagonist are substantially reduced following ganglionic blockade and restoration of blood pressure by vasopressin infusion, suggesting the a sympatholytic mechanism of action. Ongoing studies in spontaneously hypertensive rats are aimed to test whether chronic treatment with the FAAH antagonist can delay/prevent the development of cardiac hypertrophy.

我们的较早研究表明，阿甘丹胺和某些非典型大麻素配体的内皮依赖性血管扩张剂的作用，例如异常大麻二酚（ABN-CBD）是由与CB1或CB2不同的G蛋白敏感的G蛋白敏感的受体介导的。在与Mechoulam的小组合作的情况下，我们早些时候已经确定了一部小说，内源性大麻素样脑脂质，Arachidonoyl l-serine（Ara-S）。与Anandamide相反，ARA-S对CB1，CB2或Vanilloid TRPV1受体没有亲和力，并且在大鼠分离的肠系膜动脉和主动脉剂中会部分产生部分内皮依赖性血管舒张。在刚刚提交出版的最新研究中，我们分析了ARA-S对人类胚胎肾细胞中Ca2+激活的K+电流的影响，该细胞稳定地使用了人类大型电导CA2+激活的K2+激活的K+（BKCA）通道（HEK293HSLO细胞）稳定转染。 ARA-S导致大鼠的分离，完整和裸露的小肠系膜动脉（分别为PEC50：5.49和5.14）。在两种制剂中，iberiotoxin抑制了反应。在HEK293HSLO细胞中，ARA-S及其对映体N-芳基二烯酰基-D-丝氨酸以相似的效力增强了整个细胞向外K+电流（分别PEC50：5.63和5.32）。该增强不是由ARA-S代谢产物，刺激已知的大麻素受体，G蛋白，蛋白激酶或Ca2+依赖性过程的刺激，并且在斑点切除或膜胆固醇消耗后丢失，但在胆固醇重新结构后恢复。 Anandamide（AEA，PEC50：5.27）也增强了BKCA电流，但受到另一个内源性大麻素，Virodhamine（PIC50：6.35）或合成大麻素O-1918的抑制，该合成大麻素O-1918阻断了ARA-S-S-S-S-S-S-S诱导的血管舒张（PIC50：6.59）。这些发现表明（i）内源性大麻素直接调节BKCA通道或与通道相关的成分的活性。（ii）这种相互作用不涉及胞质因子，而取决于膜胆固醇（III）直接BKCA通道激活的存在可能有助于ARA-S-S诱导的肠系膜血管血管征的内皮依赖性成分。（iv）根据头部组的结构，对BKCA电流的影响是刺激性或抑制性的。（v）O-1918是一种有效的BKCA通道抑制剂。我们早些时候报道说，在健康，正常的大鼠中不影响血压，增加血压以及心脏收缩功能的CB1大麻素受体反纳斯特在3种不同的大鼠实验性高血压模型中增加了心脏收缩功能。相比之下，脂肪酸氨基水解酶（FAAH）的抑制剂是导致内源性大麻素anandamide体内降解的酶使血压升高和高血压大鼠的心脏不合适。现在，我们通过开发自己的专有FAAH拮抗剂来扩展这项研究，这在麻醉和有意识的，长期仪器的动物中都产生相似的作用更有效。我们进一步验证了这些作用是由CB1受体介导的，因为它们可以被CB1受体拮抗剂预防或急性逆转。神经节阻断和通过血管加压素输注恢复血压后，FAAH拮抗剂的降低和负肌力作用大大降低，这表明一种交感神经的作用机制。正在进行的对自发性高血压大鼠的研究旨在测试对FAAH拮抗剂的慢性治疗是否可以延迟/防止心脏肥大的发展。