目的：瘙痒是许多疾病的共同临床表现，其发生机制并未完全明确。目前认为脊髓背根神经节（DRG）神经元表达的瞬时受体电位通道（TRP）与之有关联。慢性瘙痒的治疗缺乏非常有效的方法。厚朴为祖国传统医学中治疗瘙痒有效的方剂中的重要组成之一，厚朴酚与和厚朴酚是两个主要活性成分。本研究使用组胺性和非组胺性瘙痒动物模型和TRP的激活以及瘙痒介质的分泌模型，初步探讨厚朴酚与和厚朴酚的抗瘙痒作用及其机制。

方法：采用小鼠颈背部皮内注射组胺或连续外涂乙醚/丙酮/水（AEW），分别建立组胺诱导和非组胺诱导瘙痒模型，通过计数诱导后30min内小鼠在造模部位的搔抓次数，评价不同剂量厚朴酚与和厚朴酚灌胃给药后的抗瘙痒作用。通过分离和培养原代大鼠DRG细胞，建立辣椒素（CAP）或异硫氰酸烯丙酯（AITC）激活瞬时受体电位通道V1（TRPV1）或瞬时受体电位通道A1（TRPA1）的细胞模型，用钙离子荧光成像技术观察不同浓度的厚朴酚与和厚朴酚对钙离子细胞内流的影响。同时建立CAP诱导的HaCaT细胞TRPV1活化模型，观察厚朴酚与和厚朴酚对钙离子细胞内流的影响；用poly(I:C)、rh TNF-α和rh IL-4联合刺激HaCaT细胞，建立胸腺基质淋巴细胞生成素（TSLP）的诱导分泌模式，通过ELISA检测厚朴酚与和厚朴酚对HaCaT细胞TSLP分泌的影响。

结果：颈背部皮内注射10000μM组胺成功建立了组胺诱导的小鼠瘙痒模型。50mg/kg和25mg/kg厚朴酚与和厚朴酚均明显减少瘙痒模型中小鼠的搔抓次数（与模型组相比，P＜0.05），对组胺性瘙痒的抑制率厚朴酚分别为63.65%和58.45%，和厚朴酚分别为61.82%和60.65%。每日2次，连续5天于颈背部皮肤涂抹丙酮:乙醚:水（1:1:1）成功建立AEW非组胺性小鼠瘙痒模型，两个化合物在50mg/kg剂量下明显抑制动物搔抓次数（与模型组相比，P＜0.05），抑制率分别为42.89%和39.54%；而在25mg/kg剂量下则不能明显抑制动物搔抓次数。原代培养乳大鼠的DRG细胞后，在500μM CAP或100μM AITC刺激下成功建立TRPV1或TRPA1受体通道活化模型，表现为细胞钙离子内流增加，出现相对荧光强度峰值。用15.63和31.25μg/mL厚朴酚与和厚朴酚处理后，CAP诱导出现的细胞钙离子内流减少，相对荧光强度峰值信号消失；两个化合物在31.25μg/mL时亦能抑制AITC诱导的细胞钙离子内流。500μM CAP刺激HaCaT细胞后能成功建立HaCaT细胞的TRPV1受体活化模型，31.25μg/ mL浓度的厚朴酚与和厚朴酚明显抑制CAP诱导的细胞钙离子内流。通过100 mg/L poly(I:C)、100 mg/L rh TNF-α和100 ng/mL rh IL-4的联合刺激，能成功建立HaCaT细胞TSLP的诱导分泌模式，15.63μg/mL和7.81μg/mL厚朴酚与和厚朴酚明显抑制TSLP的分泌，厚朴酚的抑制率分别为29.51%和18.61%，和厚朴酚的抑制率分别为28.41%和19.90% 。

结论：厚朴酚与和厚朴酚能减轻组胺性和非组胺性瘙痒；能抑制大鼠DRG细胞TRPV1和TRPA1通道活化；抑制HaCaT细胞TRPV1通道活化；抑制HaCaT细胞分泌瘙痒介质TSLP。两个化合物对组胺性和非组胺性瘙痒的对抗作用可能与其干扰TRP受体通道活化有关，提示，可能继而会影响后续的瘙痒动作电位在神经纤维上的传导。它们的止痒作用亦和减少HaCaT细胞分泌瘙痒相关介质TSLP有关。   

ive: itch is a common manifestation of many diseases, and the mechanism is not completely clear. it is now believed that the transient receptor potential channel (trp) expressed on spinal dorsal root ganglion (drg) neurons is associated with itch. the effective treatment of chronic itch is still lacking. magnolia is one of the important components in some traditional chinese preions which are effective for the treatment of itch. magnolol and honokiol are two important active ingredients. in this study, the anti-pruritic effects of magnolol and honokiol were evaluated by mouse itch models induced with histamine and non-histamine agents respectively. their effects on the activation of trp channels and the secretion of itch mediators were evaluated to explore some of the mechanisms of them in itch relief.

methods: histamine and non-histamine itch models were established by intradermal injection of 10000μm histamine or treatment with continuous application of acetone/ether/water (aew, 1/1/1) to rostal back of mice. the numbers of scratch was used to evaluate the anti-pruritic effect of magnolol and honokiol after intragastric administration. after the primary cultivation of rat spinal dorsal root ganglion (drg) cells, the model of activation of transient receptor potential channel v1 (trpv1) or a1 (trpa1) were established by stimulation of capsaicin (cap) or allyl isothiocyanate (aitc) respectively. the effects of magnolol and honokiol at different concentrations on calcium influx were observed by calcium fluorescence imaging system. additionally, the cap-induced trpv1 activation model of hacat keratinocytes was established and the effect of two compounds on calcium influx was also detected. the secretion of thymic stromal lymphopoietin (tslp) in hacat cells  was stimulated with the combination of poly(i:c), rh tnf-α and rh il-4. the effect of magnolol and honokiol on secretion of tslp by hacat cells was assayed.

results: magnolol and honokiol at 50mg/kg and 25mg/kg dosages significantly reduced the numbers of scratch in mice in the two pruritus models (p＜0.05 compared to the model group), and the inhibition rates of magnolol in histaminergic itch model were 63.65% and 58.45%; the rates of honokiol were 61.82% and 60.65%. in aew itch model, the two compounds at 50mg/kg significantly inhibited the scratching (with compare to the model group, p＜0.05 ), the inhibition rates were 42.89% and 39.54%, respectively; however, scratching could not be inhibited at 25mg/kg dosage. after primary culture of drg cells from newborn rat, the activation models of trpv1 and trpa1 were successfully established with the stimulation of 500 μm cap or 100 μm aitc, which showed an increase in calcium influx and a fluorescence intensity peak. after the treatment with 15.63 and 31.25 μg/ml magnolol and honokiol, the intracellular calcium influx induced by cap decreased, and the fluorescence intensity peak disappeared; the two compounds at 31.25μg/ml also inhibited aitc induced calcium influx. after stimulation with 500μm cap, magnolol and honokiol at 31.25μg/ml significantly inhibited cap-induced cellular calcium influx in hacat cells. the secretion of tslp in hacat cells was induced with the combination of 100 mg/l poly(i:c), 100 mg/l rh tnf-α and 100 ng/ml rh il-4, and magnolol and honokiol at 15.63 and 7.81μg/ml concentrations significantly inhibited the secretion of tslp, with the inhibition rates 29.51% and 18.61% of magnolol, 28.41% and 19.90% of honokiol.

conclusions: magnolol and honokiol can resist histaminergic and non-histaminergic itch. they can inhibit the activation of trpv1 and trpa1 channels in rat drg cells. the two compounds could also inhibit the activation of trpv1 and the secretion of tslp in hacat cells. their effect on histaminergic and non-histaminergic itch may be related to the reduction of calcium influx caused by the opening of trp channels. it suggests that they may affect the conduction of itch-related action potentials on nerve fibers. their antipruritic effects may also be associated with the reduction of tslp, an itch-related mediator secreted by keratinocytes.