大麻二酚在神经疾病中的分子靶点
Molecular Targets of Cannabidiol in Neurological Disorders.
作者信息
Ibeas Bih Clementino, Chen Tong, Nunn Alistair V W, Bazelot Michaël, Dallas Mark, Whalley Benjamin J
机构信息
School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK.
Broadmind Science Ltd, 47 Bow Field, Hook, Hants, RG27 9SA, UK.
出版信息
Neurotherapeutics. 2015 Oct;12(4):699-730. doi: 10.1007/s13311-015-0377-3.
Cannabis has a long history of anecdotal medicinal use and limited licensed medicinal use. Until recently, alleged clinical effects from anecdotal reports and the use of licensed cannabinoid medicines are most likely mediated by tetrahydrocannabinol by virtue of: 1) this cannabinoid being present in the most significant quantities in these preparations; and b) the proportion:potency relationship between tetrahydrocannabinol and other plant cannabinoids derived from cannabis. However, there has recently been considerable interest in the therapeutic potential for the plant cannabinoid, cannabidiol (CBD), in neurological disorders but the current evidence suggests that CBD does not directly interact with the endocannabinoid system except in vitro at supraphysiological concentrations. Thus, as further evidence for CBD's beneficial effects in neurological disease emerges, there remains an urgent need to establish the molecular targets through which it exerts its therapeutic effects. Here, we conducted a systematic search of the extant literature for original articles describing the molecular pharmacology of CBD. We critically appraised the results for the validity of the molecular targets proposed. Thereafter, we considered whether the molecular targets of CBD identified hold therapeutic potential in relevant neurological diseases. The molecular targets identified include numerous classical ion channels, receptors, transporters, and enzymes. Some CBD effects at these targets in in vitro assays only manifest at high concentrations, which may be difficult to achieve in vivo, particularly given CBD's relatively poor bioavailability. Moreover, several targets were asserted through experimental designs that demonstrate only correlation with a given target rather than a causal proof. When the molecular targets of CBD that were physiologically plausible were considered for their potential for exploitation in neurological therapeutics, the results were variable. In some cases, the targets identified had little or no established link to the diseases considered. In others, molecular targets of CBD were entirely consistent with those already actively exploited in relevant, clinically used, neurological treatments. Finally, CBD was found to act upon a number of targets that are linked to neurological therapeutics but that its actions were not consistent withmodulation of such targets that would derive a therapeutically beneficial outcome. Overall, we find that while >65 discrete molecular targets have been reported in the literature for CBD, a relatively limited number represent plausible targets for the drug's action in neurological disorders when judged by the criteria we set. We conclude that CBD is very unlikely to exert effects in neurological diseases through modulation of the endocannabinoid system. Moreover, a number of other molecular targets of CBD reported in the literature are unlikely to be of relevance owing to effects only being observed at supraphysiological concentrations. Of interest and after excluding unlikely and implausible targets, the remaining molecular targets of CBD with plausible evidence for involvement in therapeutic effects in neurological disorders (e.g., voltage-dependent anion channel 1, G protein-coupled receptor 55, CaV3.x, etc.) are associated with either the regulation of, or responses to changes in, intracellular calcium levels. While no causal proof yet exists for CBD's effects at these targets, they represent the most probable for such investigations and should be prioritized in further studies of CBD's therapeutic mechanism of action.
大麻有着悠久的民间药用历史和有限的合法药用情况。直到最近,来自民间报告和合法大麻素药物使用的所谓临床效果很可能是由四氢大麻酚介导的,原因如下:1)这种大麻素在这些制剂中含量最高;以及2)四氢大麻酚与源自大麻的其他植物大麻素之间的比例-效力关系。然而,最近人们对植物大麻素大麻二酚(CBD)在神经疾病中的治疗潜力产生了浓厚兴趣,但目前的证据表明,CBD除了在超生理浓度的体外实验中,不会直接与内源性大麻素系统相互作用。因此,随着越来越多证据表明CBD对神经疾病有益,迫切需要确定其发挥治疗作用的分子靶点。在此,我们系统检索了现有文献中描述CBD分子药理学的原创文章。我们严格评估了所提出分子靶点有效性的结果。此后,我们考虑了所确定的CBD分子靶点在相关神经疾病中是否具有治疗潜力。所确定的分子靶点包括众多经典的离子通道、受体、转运体和酶。在体外实验中,CBD在这些靶点上的一些作用仅在高浓度下才会显现,而在体内可能难以达到这种浓度,特别是考虑到CBD相对较差的生物利用度。此外,一些靶点是通过仅表明与给定靶点存在相关性而非因果关系的实验设计确定的。当考虑CBD在生理上合理的分子靶点在神经治疗中的开发潜力时,结果各不相同。在某些情况下,所确定的靶点与所考虑的疾病几乎没有或没有既定联系。在其他情况下,CBD的分子靶点与相关临床应用的神经治疗中已经积极开发的靶点完全一致。最后,发现CBD作用于一些与神经治疗相关的靶点,但其作用与调节这些靶点以产生治疗有益结果不一致。总体而言,我们发现,虽然文献中已报道了超过65个不同的CBD分子靶点,但根据我们设定的标准判断,在神经疾病中,相对有限的数量代表了该药物作用的合理靶点。我们得出结论,CBD极不可能通过调节内源性大麻素系统在神经疾病中发挥作用。此外,文献中报道的许多其他CBD分子靶点不太可能具有相关性,因为其作用仅在超生理浓度下才能观察到。有趣的是,在排除不太可能和不合理的靶点后,CBD在神经疾病治疗作用中具有合理证据的其余分子靶点(例如,电压依赖性阴离子通道1、G蛋白偶联受体55、CaV3.x等)与细胞内钙水平的调节或对其变化的反应有关。虽然尚无CBD在这些靶点上作用的因果证据,但它们是此类研究中最有可能的靶点,应在CBD治疗作用机制的进一步研究中优先考虑。