Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada.
Cannabis Cannabinoid Res. 2024 Feb;9(1):174-187. doi: 10.1089/can.2022.0125. Epub 2022 Oct 11.
Cannabis use has been associated with an increased incidence of psychiatric disorders, yet the underlying neurobiological processes mediating these associations are poorly understood. Whereas exposure to Δ9-tetrahydrocannabinol (THC) has been associated with the development or exacerbation of psychosis, treatment with cannabidiol (CBD) has been associated with amelioration of psychosis. In this study, we demonstrate a complex effect of CBD in mouse models of psychosis, based on factors, including dose, strain, and genotype. Adult GluN1 knockdown (GluN1KD) and dopamine transporter knockout (DATKO) mice (almost equally balanced for male/female) were acutely treated with vehicle, THC (4 mg/kg), CBD (60, 120 mg/kg), or THC:CBD (1:15, 4:60 mg/kg) and tested in behavioral assays. GluN1KD and DATKO mice displayed hyperactivity, impaired habituation, and sensorimotor gating, along with increased stereotypy and vertical activity. THC, alone and in combination with CBD, produced a robust "dampening" effect on the exploratory behavior regardless of strain or genotype. CBD exhibited a more complex profile. At 60 mg/kg, CBD had minimal effects on horizontal activity, but the effects varied in terms of directionality (increase vs. decrease) in other parameters; effects on stereotypic behaviors differ by genotype, while effects on vertical exploration differ by strain×genotype. CBD at 120 mg/kg had a "dampening" effect on exploration overall, except in GluN1KD mice, where no effect was observed. In terms of sensorimotor gating, both THC and CBD had minimal effects, except for 120 mg/kg CBD, which exacerbated the acoustic startle response. Here, we present a study that highlights the complex mechanism of phytocannabinoids, particularly CBD, in models of psychosis-like behavior. These data require careful interpretation, as agonism of the cannabinoid receptor 1 (CB) resulting in a decrease in locomotion can be misinterpreted as "antipsychotic-like" activity in murine behavioral outputs of psychosis. Importantly, the THC-mediated decrease in hyperexploratory behavior observed in our models (alone or in combination) was not specific to the genetic mutants, but rather was observed regardless of strain or genotype. Furthermore, CBD treatment, when comparing mutants with their wild-type littermate controls, showed little to no "antipsychotic-like" activity in our models. Therefore, it is not only important to consider dose when designing/interpreting therapeutically driven phytocannabinoid studies, but also effects of strain or genetic vulnerability respective to the general population.
大麻的使用与精神障碍发生率的增加有关,但介导这些关联的潜在神经生物学过程知之甚少。虽然接触 Δ9-四氢大麻酚(THC)与精神病的发展或恶化有关,但大麻二酚(CBD)的治疗与精神病的改善有关。在这项研究中,我们基于剂量、品系和基因型等因素,在精神疾病模型的小鼠中证明了 CBD 的复杂作用。 成年 GluN1 敲低(GluN1KD)和多巴胺转运蛋白敲除(DATKO)小鼠(雄性/雌性几乎相等)接受 vehicle、THC(4mg/kg)、CBD(60、120mg/kg)或 THC:CBD(1:15、4:60mg/kg)的急性治疗,并在行为测定中进行测试。GluN1KD 和 DATKO 小鼠表现出过度活跃、习惯形成受损和感觉运动门控障碍,以及刻板行为和垂直活动增加。THC 单独和与 CBD 联合使用,无论品系或基因型如何,都会对探索行为产生强烈的“抑制”作用。CBD 表现出更复杂的特征。在 60mg/kg 时,CBD 对水平活动的影响很小,但在其他参数的方向性(增加与减少)方面存在差异;对刻板行为的影响因基因型而异,而对垂直探索的影响因品系×基因型而异。120mg/kg 的 CBD 对整体探索有“抑制”作用,但在 GluN1KD 小鼠中没有观察到这种作用。在感觉运动门控方面,THC 和 CBD 都只有很小的作用,除了 120mg/kg 的 CBD,它加剧了听觉惊吓反应。 在这里,我们提出了一项研究,强调了植物大麻素,特别是 CBD,在类精神病行为模型中的复杂机制。这些数据需要仔细解释,因为大麻素受体 1(CB)的激动作用导致运动减少可能被误解为小鼠精神病行为输出中的“抗精神病样”活性。重要的是,我们模型中观察到的 THC 介导的过度探索行为减少(单独或联合)不仅与遗传突变体有关,而且与品系或基因型无关。此外,与野生型同窝仔对照相比,CBD 治疗在我们的模型中显示出很少或没有“抗精神病样”活性。因此,在设计/解释治疗驱动的植物大麻素研究时,不仅要考虑剂量,还要考虑到与一般人群相关的品系或遗传易感性的影响。