Bladen Chris, McDaniel Steven W, Gadotti Vinicius M, Petrov Ravil R, Berger N Daniel, Diaz Philippe, Zamponi Gerald W
Department of Physiology & Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary , Calgary, AB T2N 1N4, Canada.
ACS Chem Neurosci. 2015 Feb 18;6(2):277-87. doi: 10.1021/cn500206a. Epub 2014 Nov 5.
Low-voltage-activated (T-type) calcium channels are important regulators of the transmission of nociceptive information in the primary afferent pathway and finding ligands that modulate these channels is a key focus of the drug discovery field. Recently, we characterized a set of novel compounds with mixed cannabinoid receptor/T-type channel blocking activity and examined their analgesic effects in animal models of pain. Here, we have built on these previous findings and synthesized a new series of small organic compounds. We then screened them using whole-cell voltage clamp techniques to identify the most potent T-type calcium channel inhibitors. The two most potent blockers (compounds 9 and 10) were then characterized using radioligand binding assays to determine their affinity for CB1 and CB2 receptors. The structure-activity relationship and optimization studies have led to the discovery of a new T-type calcium channel blocker, compound 9. Compound 9 was efficacious in mediating analgesia in mouse models of acute inflammatory pain and in reducing tactile allodynia in the partial nerve ligation model. This compound was shown to be ineffective in Cav3.2 T-type calcium channel null mice at therapeutically relevant concentrations, and it caused no significant motor deficits in open field tests. Taken together, our data reveal a novel class of compounds whose physiological and therapeutic actions are mediated through block of Cav3.2 calcium channels.
低电压激活（T型）钙通道是初级传入通路中伤害性信息传递的重要调节因子，寻找能够调节这些通道的配体是药物研发领域的一个关键重点。最近，我们鉴定了一组具有混合大麻素受体/T型通道阻断活性的新型化合物，并在疼痛动物模型中研究了它们的镇痛作用。在此，我们基于这些先前的发现，合成了一系列新的有机小分子化合物。然后，我们使用全细胞膜片钳技术对它们进行筛选，以鉴定出最有效的T型钙通道抑制剂。随后，使用放射性配体结合试验对两种最有效的阻滞剂（化合物9和10）进行表征，以确定它们对CB1和CB2受体的亲和力。结构-活性关系和优化研究导致发现了一种新的T型钙通道阻滞剂——化合物9。化合物9在急性炎性疼痛小鼠模型中介导镇痛有效，并且在部分神经结扎模型中可减轻触觉异常性疼痛。在治疗相关浓度下，该化合物在Cav3.2 T型钙通道缺失小鼠中无效，并且在旷场试验中未引起明显的运动缺陷。综上所述，我们的数据揭示了一类新型化合物，其生理和治疗作用是通过阻断Cav3.2钙通道介导的。
