Objective: To investigate the effects of umbilical moxibustion therapy on phobic behavior and the contents of norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) in different brain regions of the stress-model rats and explore the potential mechanism of umbilical moxibustion on phobic behavior.
Methods: Among 50 Wistar male rats, 45 rates were selected and randomly divided into a control group, a model group and an umbilical moxibustion group, 15 rats in each one; and the rest 5 rats were used for preparing the model of electric shock. The bystander electroshock method was adopted to prepare phobic stress model in the model group and the umbilical moxibustion group. After modeling, the intervention with umbilical moxibustion started in the umbilical moxibustion group, in which, the ginger-isolated moxibustion was applied at "Shenque" (CV 8), once daily, 2 cones for 20 min each time, for consecutively 21 days. After modeling and intervention completed, the rats in each group were subjected to the open field test to evaluate the state of fear. After intervention, the Morris water maze test and fear conditioning test were performed to evaluate the changes in learning and memory ability and the state of fear. Using high performance liquid chromatography (HPLC), the contents of NE, DA and 5-HT in the hippocampus, prefrontal cortex and hypothalamus were determined.
Results: Compared with the control group, the horizontal and vertical activity scores were lower (P<0.01), the number of stool particles was increased (P<0.01), the escape latency was prolonged (P<0.01), the times of target quadrant were reduced (P<0.01), and the freezing time was prolonged (P<0.05) in the rats of the model group. The horizontal and vertical activity scores were increased (P<0.05), the number of stool particles was reduced (P<0.05), the escape latency was shortened (P<0.05, P<0.01), the times of target quadrant were increased (P<0.05), and the freezing time was shortened (P<0.05) in the rats of the umbilical moxibustion group when compared with the model group. The trend search strategy was adopted in the control group and the umbilical moxibustion group, while the random search strategy was used in rats of the model group. Compared with the control group, the contents of NE, DA and 5-HT in the hippocampus, prefrontal cortex and hypothalamus were reduced (P<0.01) in the model group. In the umbilical moxibustion group, the contents of NE, DA and 5-HT in the hippocampus, prefrontal cortex and hypothalamus were increased (P<0.05, P<0.01) when compared with the model group.
Conclusion: Umbilical moxibustion can effectively relieve the state of fear and learning and memory impairment of phobic stress model rats, which may be related to the up-regulation of contents of brain neurotransmitters, i.e. NE, DA, and 5-HT.
目的：观察脐灸疗法对应激模型大鼠恐惧样行为的改善作用及对不同脑区神经递质去甲肾上腺素（NE）、多巴胺（DA）、5-羟色胺（5-HT）含量的影响，探讨脐灸改善恐惧样行为的潜在机制。方法：从50只Wistar雄性大鼠中选取45只随机分为空白组、模型组和脐灸组，每组15只，剩余5只作为电击鼠制备模型。模型组和脐灸组均采用旁观电击法制备恐惧应激模型，脐灸组于造模结束后开始脐灸干预，于“神阙”行隔姜灸，每次灸2壮，每次20 min，每天1次，持续21 d。造模后、干预后进行旷场实验评价大鼠恐惧状态；干预后，进行Morris水迷宫实验和场景恐惧实验评价大鼠学习记忆能力和恐惧状态，高效液相色谱法测定各组大鼠海马、前额叶皮质、下丘脑NE、DA、5-HT含量。结果：与空白组比较，模型组大鼠水平活动评分、垂直活动评分降低（P<0.01），大便粒数增加（P<0.01），逃避潜伏期延长（P<0.01），进入目标象限次数减少（P<0.01），冻结时间延长（P<0.05）；与模型组比较，脐灸组大鼠水平活动评分、垂直活动评分升高（P<0.05），大便粒数减少（P<0.05），逃避潜伏期缩短（P<0.05，P<0.01），进入目标象限次数增加（P<0.05），冻结时间缩短（P<0.05）。空白组和脐灸组大鼠多采用趋向式搜索策略，模型组大鼠多采用随机式搜索策略。与空白组比较，模型组大鼠海马、前额叶皮质及下丘脑NE、DA、5-HT含量降低（P<0.01）；与模型组比较，脐灸组大鼠海马、前额叶皮质及下丘脑NE、DA、5-HT含量升高（P<0.05，P<0.01）。结论：脐灸可有效改善恐惧应激模型大鼠的恐惧状态和学习记忆能力，其机制可能与上调脑内神经递质NE、DA、5-HT含量有关。.
Keywords: 5-hydroxytryptamine (5-HT); dopamine (DA); neurotransmitters; norepinephrine (NE); phobic stress; umbilical moxibustion.