目的:探讨寒热中药的成分与TRP家族中TRPV1和TRPM8通道蛋白mRNA表达的相关性。方法:原代培养DRG神经元,在体外观察中药单体对通道蛋白表达的影响,基因的表达量采用荧光定量PCR(real time PCR)法检测,数据分析采用2?ΔΔCT法。结果:热性...目的:探讨寒热中药的成分与TRP家族中TRPV1和TRPM8通道蛋白mRNA表达的相关性。方法:原代培养DRG神经元,在体外观察中药单体对通道蛋白表达的影响,基因的表达量采用荧光定量PCR(real time PCR)法检测,数据分析采用2?ΔΔCT法。结果:热性中药的成分(吴茱萸碱、桂皮醛)上调TRPV1的表达,下调TRPM8的表达,尤以寒负荷后更为明显;寒性中药的成分(黄芩苷、大黄素)上调TRPM8的表达,下调TRPV1的表达,尤以热负荷后更为明显。结论:对TRPV1与TR-PM8的表达调节可能与中药的寒热药性相关,这可能是寒热性中药临床上发挥寒热调节作用的机制之一。展开更多
Capsaicin in chili peppers bestows the sensation of spiciness. Since the discovery of its receptor, transient receptor potential vanilloid 1 （TRPV1） ion channel, how capsaicin activates this channel has been under e...Capsaicin in chili peppers bestows the sensation of spiciness. Since the discovery of its receptor, transient receptor potential vanilloid 1 （TRPV1） ion channel, how capsaicin activates this channel has been under extensive investigation using a variety of experimental techniques including mutagenesis, patch-clamp recording, crystallography, cryo-electron microscopy, computational docking and molecular dynamic simu- lation. A framework of how capsaicin binds and acti- vates TRPV1 has started to merge： capsaicin binds to a pocket formed by the channel＇s transmembrane seg- ments, where it takes a ＂tail-up, head-down＂ configu- ration. Binding is mediated by both hydrogen bonds and van der Waals interactions. Upon binding, cap- saicin stabilizes the open state of TRPV1 by ＂pull-and- contact＂ with the $4-$5 linker. Understanding the ligand-host interaction will greatly facilitate pharma- ceutical efforts to develop novel analgesics targeting TRPV1.展开更多
Objective Our previous study showed that tumor tissue-derived formaldehyde at low concentrations plays an important role in bone cancer pain through activating transient receptor potential vanilloid subfamily member 1...Objective Our previous study showed that tumor tissue-derived formaldehyde at low concentrations plays an important role in bone cancer pain through activating transient receptor potential vanilloid subfamily member 1 （TRPV 1）. The present study further explored whether this tumor tissue-derived endogenous formaldehyde regulates TRPV1 expres- sion in a rat model of bone cancer pain, and if so, what the possible signal pathways are during the development of this type of pain. Methods A rat model of bone cancer pain was established by injecting living MRMT-1 tumor cells into the tibia. The formaldehyde levels were determined by high performance liquid chromatography, and the expression of TRPV1 was examined with Western blot and RT-PCR. In primary cultured dorsal root ganglion （DRG） neurons, the ex- pression of TRPV1 was assessed after treatment with 100 ~tmol/L formaldehyde with or without pre-addition of PD98059 [an inhibitor for extracellular signal-regulated kinase], SB203580 （a p38 inhibitor）, SP600125 [an inhibitor for c-Jun N- terminal kinase], BIM [a protein kinase C （PKC） inhibitor] or LY294002 [a phosphatidylinositol 3-kinase （PI3K） inhibi- tor]. Results In the rat model of bone cancer pain, formaldehyde concentration increased in blood plasma, bone marrow and the spinal cord. TRPV1 protein expression was also increased in the DRG. In primary cultured DRG neurons, 100 p^mol/L formaldehyde significantly increased the TRPV1 expression level. Pre-incubation with PD98059, SB203580, SP600125 or LY294002, but not BIM, inhibited the formaldehyde-induced increase of TRPV1 expression. Conclusion Formaldehyde at a very low concentration up-regulates TRPV1 expression through mitogen-activated protein kinase and PI3K, but not PKC, signaling pathways. These results further support our previous finding that TRPV1 in peripheral after- ents plays a role in bone cancer pain.展开更多
Objective To investigate the role of oxidative stress in itch-indicative scratching behavior in mice, and further- more, to define the cellular and molecular mechanisms underlying oxidative stress-mediated itch. Metho...Objective To investigate the role of oxidative stress in itch-indicative scratching behavior in mice, and further- more, to define the cellular and molecular mechanisms underlying oxidative stress-mediated itch. Methods Scratching behavior was induced by intradermal injection of the oxidants hydrogen peroxide （H202） or tert-butylhydroperoxide （tBHP） into the nape of the neck in mice. The mice were observed for 30 rain. Results Intradermal H202 （0.03%-1%） or tBHP （1-30 pmol） elicited robust scratching behavior, displaying an inverted U-shaped dose-response curve. Naloxone, an opioid receptor antagonist, but not morphine, largely suppressed the oxidant-induced scratching. Chlorpheniramine, a histamine H1 receptor antagonist, blocked histamine- but not oxidant-induced scratching, indicating the involvement of a histamine-independent mechanism in oxidant-evoked itch. Further, resiniferatoxin treatment abolished oxidant-induced scratching, suggesting an essential role of C-fibers. Notably, blockade of transient receptor potential subtype ankyrin 1 （TRPA1） with the selective TRPA1 antagonist HC-030031, or genetic deletion of Trpal but not Trpvl （subfamily V, mem- ber 1） resulted in a profound reduction in H202-evoked scratching. Finally, systemic administration of the antioxidant N- acetyl-L-cysteine or trolox （a water-soluble vitamin E analog） attenuated scratching induced by the oxidants. Conclusion Oxidative stress by different oxidants induces profound scratching behavior, which is largely histamine- and TRPV1- independent but TRPAl-dependent. Antioxidants and TRPA1 antagonists may be used to treat human itch conditions as- sociated with oxidative stress.展开更多
Puerarin is a major active ingredient of the traditional Chinese plant medicine,Radix Puerariae,and commonly used in the treatment of myocardial and cerebral ischemia.However,the effects of puerarin on neuropathic pai...Puerarin is a major active ingredient of the traditional Chinese plant medicine,Radix Puerariae,and commonly used in the treatment of myocardial and cerebral ischemia.However,the effects of puerarin on neuropathic pain are still unclear.In this study,a neuropathic pain animal model was created by partial sciatic nerve ligation.Puerarin（30 or 60 mg/kg） was intraperitoneally injected once a day for 7 days.Mechanical allodynia and thermal hyperalgesia were examined at 1 day after model establishment.Mechanical threshold and paw withdrawal latency markedly increased in a dose-dependent manner in puerarin-treated rats,especially at 7 days after model establishment.At 7 days after model establishment,quantitative real-time reverse transcriptase-polymerase chain reaction results showed that puerarin administration reversed m RNA expression of transient receptor potential vanilloid 1（Trpv1） and transient receptor potential ankyrin 1（Trpa1） in a dose-dependent manner in dorsal root ganglion neurons after peripheral nerve injury.These results suggest that puerarin dose-dependently ameliorates neuropathic pain by suppressing Trpv1 and Trpa1 up-regulation in dorsal root ganglion of neuropathic pain rats.展开更多
文摘目的:探讨寒热中药的成分与TRP家族中TRPV1和TRPM8通道蛋白mRNA表达的相关性。方法:原代培养DRG神经元,在体外观察中药单体对通道蛋白表达的影响,基因的表达量采用荧光定量PCR(real time PCR)法检测,数据分析采用2?ΔΔCT法。结果:热性中药的成分(吴茱萸碱、桂皮醛)上调TRPV1的表达,下调TRPM8的表达,尤以寒负荷后更为明显;寒性中药的成分(黄芩苷、大黄素)上调TRPM8的表达,下调TRPV1的表达,尤以热负荷后更为明显。结论:对TRPV1与TR-PM8的表达调节可能与中药的寒热药性相关,这可能是寒热性中药临床上发挥寒热调节作用的机制之一。
文摘Capsaicin in chili peppers bestows the sensation of spiciness. Since the discovery of its receptor, transient receptor potential vanilloid 1 （TRPV1） ion channel, how capsaicin activates this channel has been under extensive investigation using a variety of experimental techniques including mutagenesis, patch-clamp recording, crystallography, cryo-electron microscopy, computational docking and molecular dynamic simu- lation. A framework of how capsaicin binds and acti- vates TRPV1 has started to merge： capsaicin binds to a pocket formed by the channel＇s transmembrane seg- ments, where it takes a ＂tail-up, head-down＂ configu- ration. Binding is mediated by both hydrogen bonds and van der Waals interactions. Upon binding, cap- saicin stabilizes the open state of TRPV1 by ＂pull-and- contact＂ with the $4-$5 linker. Understanding the ligand-host interaction will greatly facilitate pharma- ceutical efforts to develop novel analgesics targeting TRPV1.
基金supported by grants from the National Natural Science Foundation of China (81070893, 81171042 and 31171063)Beijing Municipal Commission of Education "Grants for Outstanding Ph.D. Program Tutors"+2 种基金the "111" Project of the Ministry of Education of ChinaThe Ministry of Education(BMU20100014)the China Postdoctoral Science Foundation (20090450266)
文摘Objective Our previous study showed that tumor tissue-derived formaldehyde at low concentrations plays an important role in bone cancer pain through activating transient receptor potential vanilloid subfamily member 1 （TRPV 1）. The present study further explored whether this tumor tissue-derived endogenous formaldehyde regulates TRPV1 expres- sion in a rat model of bone cancer pain, and if so, what the possible signal pathways are during the development of this type of pain. Methods A rat model of bone cancer pain was established by injecting living MRMT-1 tumor cells into the tibia. The formaldehyde levels were determined by high performance liquid chromatography, and the expression of TRPV1 was examined with Western blot and RT-PCR. In primary cultured dorsal root ganglion （DRG） neurons, the ex- pression of TRPV1 was assessed after treatment with 100 ~tmol/L formaldehyde with or without pre-addition of PD98059 [an inhibitor for extracellular signal-regulated kinase], SB203580 （a p38 inhibitor）, SP600125 [an inhibitor for c-Jun N- terminal kinase], BIM [a protein kinase C （PKC） inhibitor] or LY294002 [a phosphatidylinositol 3-kinase （PI3K） inhibi- tor]. Results In the rat model of bone cancer pain, formaldehyde concentration increased in blood plasma, bone marrow and the spinal cord. TRPV1 protein expression was also increased in the DRG. In primary cultured DRG neurons, 100 p^mol/L formaldehyde significantly increased the TRPV1 expression level. Pre-incubation with PD98059, SB203580, SP600125 or LY294002, but not BIM, inhibited the formaldehyde-induced increase of TRPV1 expression. Conclusion Formaldehyde at a very low concentration up-regulates TRPV1 expression through mitogen-activated protein kinase and PI3K, but not PKC, signaling pathways. These results further support our previous finding that TRPV1 in peripheral after- ents plays a role in bone cancer pain.
基金supported by grants from the National Natural Science Foundation of China(No. 3153002 30925015+3 种基金 30830044 31771295 and 31371143)the National Basic Research Development Program of China (No. 2014CB542204)
基金supported by grants from the US National Institutes of Health (R01-DE17794,R01-NS54362 and R01-NS67686)
文摘Objective To investigate the role of oxidative stress in itch-indicative scratching behavior in mice, and further- more, to define the cellular and molecular mechanisms underlying oxidative stress-mediated itch. Methods Scratching behavior was induced by intradermal injection of the oxidants hydrogen peroxide （H202） or tert-butylhydroperoxide （tBHP） into the nape of the neck in mice. The mice were observed for 30 rain. Results Intradermal H202 （0.03%-1%） or tBHP （1-30 pmol） elicited robust scratching behavior, displaying an inverted U-shaped dose-response curve. Naloxone, an opioid receptor antagonist, but not morphine, largely suppressed the oxidant-induced scratching. Chlorpheniramine, a histamine H1 receptor antagonist, blocked histamine- but not oxidant-induced scratching, indicating the involvement of a histamine-independent mechanism in oxidant-evoked itch. Further, resiniferatoxin treatment abolished oxidant-induced scratching, suggesting an essential role of C-fibers. Notably, blockade of transient receptor potential subtype ankyrin 1 （TRPA1） with the selective TRPA1 antagonist HC-030031, or genetic deletion of Trpal but not Trpvl （subfamily V, mem- ber 1） resulted in a profound reduction in H202-evoked scratching. Finally, systemic administration of the antioxidant N- acetyl-L-cysteine or trolox （a water-soluble vitamin E analog） attenuated scratching induced by the oxidants. Conclusion Oxidative stress by different oxidants induces profound scratching behavior, which is largely histamine- and TRPV1- independent but TRPAl-dependent. Antioxidants and TRPA1 antagonists may be used to treat human itch conditions as- sociated with oxidative stress.
基金supported by the National Natural Science Foundation of China,No.81671891
文摘Puerarin is a major active ingredient of the traditional Chinese plant medicine,Radix Puerariae,and commonly used in the treatment of myocardial and cerebral ischemia.However,the effects of puerarin on neuropathic pain are still unclear.In this study,a neuropathic pain animal model was created by partial sciatic nerve ligation.Puerarin（30 or 60 mg/kg） was intraperitoneally injected once a day for 7 days.Mechanical allodynia and thermal hyperalgesia were examined at 1 day after model establishment.Mechanical threshold and paw withdrawal latency markedly increased in a dose-dependent manner in puerarin-treated rats,especially at 7 days after model establishment.At 7 days after model establishment,quantitative real-time reverse transcriptase-polymerase chain reaction results showed that puerarin administration reversed m RNA expression of transient receptor potential vanilloid 1（Trpv1） and transient receptor potential ankyrin 1（Trpa1） in a dose-dependent manner in dorsal root ganglion neurons after peripheral nerve injury.These results suggest that puerarin dose-dependently ameliorates neuropathic pain by suppressing Trpv1 and Trpa1 up-regulation in dorsal root ganglion of neuropathic pain rats.
