Jhaveri M D, Richardson D, Chapman V
School of Biomedical Sciences, Institute of Neuroscience, Queens Medical Centre, Nottingham, UK.
Br J Pharmacol. 2007 Nov;152(5):624-32. doi: 10.1038/sj.bjp.0707433. Epub 2007 Aug 20.
Cannabinoid CB1 and CB2 receptors are located at key sites involved in the relaying and processing of noxious inputs. Both CB1 and CB2 receptor agonists have analgesic effects in a range of models of inflammatory and neuropathic pain. Importantly, clinical trials of cannabis-based medicines indicate that the pre-clinical effects of cannabinoid agonists may translate into therapeutic potential in humans. One of the areas of concern with this pharmacological approach is that CB1 receptors have a widespread distribution in the brain and that global activation of CB1 receptors is associated with adverse side effects. Studies of the endogenous cannabinoids (endocannabinoids) have demonstrated that they are present in most tissues and that in some pain states, such as neuropathic pain, levels of endocannabinoids are elevated at key sites involved in pain processing. An alternative approach that can be used to harness the potential therapeutic effects of cannabinoids is to maximise the effects of the endocannabinoids, the actions of which are terminated by re-uptake and metabolism by various enzymes, including fatty acid amide hydrolase (FAAH), monoacylglycerol lipase (MAGL) and cyclooxygenase type 2 (COX2). Preventing the metabolism, or uptake, of endocannabinoids elevates levels of these lipid compounds in tissue and produces behavioural analgesia in models of acute pain. Herein we review recent studies of the effects of inhibition of metabolism of endocannabinoids versus uptake of endocannabinoids on nociceptive processing in models of inflammatory and neuropathic pain.
大麻素CB1和CB2受体位于参与有害刺激输入传递和处理的关键部位。CB1和CB2受体激动剂在一系列炎症性和神经性疼痛模型中均具有镇痛作用。重要的是,基于大麻的药物的临床试验表明,大麻素激动剂的临床前效应可能转化为对人类的治疗潜力。这种药理学方法的一个关注点是,CB1受体在大脑中广泛分布,并且CB1受体的整体激活与不良副作用相关。对内源性大麻素(内源性大麻素)的研究表明,它们存在于大多数组织中,并且在某些疼痛状态下,例如神经性疼痛,内源性大麻素的水平在参与疼痛处理的关键部位会升高。一种可用于利用大麻素潜在治疗作用的替代方法是最大化内源性大麻素的作用,其作用通过包括脂肪酸酰胺水解酶(FAAH)、单酰甘油脂肪酶(MAGL)和环氧合酶2型(COX2)在内的各种酶的再摄取和代谢而终止。防止内源性大麻素的代谢或摄取会提高组织中这些脂质化合物的水平,并在急性疼痛模型中产生行为性镇痛作用。在此,我们综述了近期关于抑制内源性大麻素代谢与内源性大麻素摄取对炎症性和神经性疼痛模型中伤害性处理影响的研究。