Primidone inhibits TRPM3 and attenuates thermal nociception in vivo.
Primidone inhibits TRPM3 and attenuates thermal nociception in vivo.
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DOI：
10.1097/j.pain.0000000000000846
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发表时间：
2017-05
期刊：
影响因子：
7.4
通讯作者：
Schaefer M
中科院分区：
文献类型：
--
作者：
Krügel U;Straub I;Beckmann H;Schaefer M
补充数字内容在文本中可用。批准的抗癫痫药物扑米酮有效地抑制TRPM3通道，从而对小鼠的化学疼痛和热痛觉过敏发挥镇痛作用。Melastatin相关的瞬时受体电位（TRP）通道TRPM 3是一种非选择性阳离子通道，在伤害性神经元中表达，并被热激活。由于TRPM3缺陷小鼠表现出炎性热痛觉过敏，TRPM3的药理学抑制可能发挥抗伤害感受特性。使用荧光Ca2+内流测定和含有经批准或临床测试的药物的化合物库来鉴定TRPM3抑制剂。使用电生理学方法评估通道抑制的生物物理特性。非甾体抗炎药双氯芬酸、四环抗抑郁药马普替林和抗惊厥药扑米酮被确定为高效TRPM3阻断剂，在0.6至6 μM时具有半数最大抑制作用，对TRPM3具有显著特异性。最突出的是，扑米酮在显著低于抗癫痫治疗中常用的血浆浓度的浓度下具有抑制TRPM3被硫酸双烯醇酮（PregS）和热激活的生物活性。扑米酮通过别构调节阻断PregS诱导的Ca2+i通过TRPM3内流，并可逆地抑制PregS和克霉唑联合诱导的非典型内向整流TRPM3电流。在体内，低剂量扑米酮的镇痛作用在小鼠中得到证实，应用PregS和热诱导的疼痛模型，包括炎性痛觉过敏。因此，以低于诱导抗惊厥作用所需的浓度应用批准的药物为研究TRPM 3在体内的生理和病理生理作用提供了捷径。
Supplemental Digital Content is Available in the Text. The approved antiepileptic drug primidone potently inhibits TRPM3 channels and thereby exerts analgesic properties to chemical pain and thermal hyperalgesia in mice. The melastatin-related transient receptor potential (TRP) channel TRPM3 is a nonselective cation channel expressed in nociceptive neurons and activated by heat. Because TRPM3-deficient mice show inflammatory thermal hyperalgesia, pharmacological inhibition of TRPM3 may exert antinociceptive properties. Fluorometric Ca2+ influx assays and a compound library containing approved or clinically tested drugs were used to identify TRPM3 inhibitors. Biophysical properties of channel inhibition were assessed using electrophysiological methods. The nonsteroidal anti-inflammatory drug diclofenac, the tetracyclic antidepressant maprotiline, and the anticonvulsant primidone were identified as highly efficient TRPM3 blockers with half-maximal inhibition at 0.6 to 6 μM and marked specificity for TRPM3. Most prominently, primidone was biologically active to suppress TRPM3 activation by pregnenolone sulfate (PregS) and heat at concentrations markedly lower than plasma concentrations commonly used in antiepileptic therapy. Primidone blocked PregS-induced Ca2+i influx through TRPM3 by allosteric modulation and reversibly inhibited atypical inwardly rectifying TRPM3 currents induced by coapplication of PregS and clotrimazole. In vivo, analgesic effects of low doses of primidone were demonstrated in mice, applying PregS- and heat-induced pain models, including inflammatory hyperalgesia. Thus, applying the approved drug at concentrations that are lower than those needed to induce anticonvulsive effects offers a shortcut for studying physiological and pathophysiological roles of TRPM3 in vivo.