Behavioral Effects of Continuously Administered Bergamot Essential Oil on Mice With Partial Sciatic Nerve Ligation
Behavioral Effects of Continuously Administered Bergamot Essential Oil on Mice With Partial Sciatic Nerve Ligation
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DOI：
10.3389/fphar.2020.01310
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发表时间：
2020-08-21
影响因子：
5.6
通讯作者：
Sakurada, Tsukasa
中科院分区：
文献类型：
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作者：
Hamamura, Kengo;Katsuyama, Soh;Sakurada, Tsukasa
神经病理性疼痛是一种主要由异常性疼痛引起的顽固性慢性疼痛。我们以前曾报道，足底内给予佛手柑精油（BEO）含有芳香族化合物显着抑制部分坐骨神经结扎（PSNL）诱导的机械异常性疼痛阿片类μ受体在小鼠中。然而，也有报道称，吸入BEO可降低福尔马林诱导的伤害性反应。因此，我们旨在阐明BEO的镇痛作用是否通过挥发性成分的嗅觉刺激介导。在本研究中，在PSNL手术期间，使用渗透泵连续给予BEO，并使用双活动监测系统检查对小鼠行为的影响，该系统可以使用红外光束传感器检测笼中的二维平面运动以及使用转轮检测主动运动。在这里，我们报告说，二维平面活动显着增加与PSNL小鼠在光相（从8点到20点），但不是在黑暗阶段（从20点到8点）从手术后的第二天。然而，当连续给予BEO时，未观察到这种增加。盐酸纳洛酮可拮抗BEO对PSNL小鼠二维平面计数的影响。关于转轮活动，从术后第8天开始，在黑暗阶段旋转次数减少。然而，这在使用BEO时并不明显。盐酸纳洛酮可拮抗BEO对旋转数的影响。此外，在PSNL小鼠中吸入BEO不影响机械性异常性疼痛或二维平面运动或转轮活动。这些结果表明，BEO表现出镇痛作用，这是由阿片受体介导的，而不是由嗅觉系统。
Neuropathic pain is an intractable chronic pain condition that is mainly caused by allodynia. We had previously reported that intra-plantar administration of bergamot essential oil (BEO) containing an aromatic compound significantly suppressed partial sciatic nerve ligation (PSNL)-induced mechanical allodyniaviaopioid mu receptors in mice. However, it has also been reported that the inhalation of BEO reduced formalin-induced nociceptive responses. Therefore, we aimed to elucidate whether the analgesic action of BEO is mediated by olfactory stimulation through volatile components. In the current study, BEO was continuously administered with an osmotic pump during PSNL surgery, and the effects on mice behavior were examined pharmacologically using a double activity monitoring system, which can detect two-dimensional planar motion in a cage with an infrared beam sensor as well as active motion with a running wheel. Here, we report that the two-dimensional planar activity significantly increased in mice with PSNL in the light phase (from 8 o'clock to 20 o'clock) but not in the dark phase (from 20 o'clock to 8 o'clock) from the second day after surgery. However, this increase was not observed when BEO was continuously administered. The effect of BEO on the two-dimensional planar counts in mice with PSNL was antagonized by naloxone hydrochloride. Regarding the running wheel activity, the number of rotations decreased by PSNL in the dark phase from the 8th day after surgery. However, this was not apparent with BEO use. The effect of BEO on the number of rotations was also antagonized by naloxone hydrochloride. Furthermore, inhalation of BEO in PSNL mice did not affect mechanical allodynia or the two-dimensional planar motion or running wheel activities. These findings indicate that BEO exhibits an analgesic action, which is mediated by opioid receptors and not by the olfactory system.