The transient receptor potential cation channel subfamily V member 1（TRPV1） provides the sensation of pain（nociception）. However, it remains unknown whether TRPV1 is activated after peripheral nerve injury, or whe...The transient receptor potential cation channel subfamily V member 1（TRPV1） provides the sensation of pain（nociception）. However, it remains unknown whether TRPV1 is activated after peripheral nerve injury, or whether activation of TRPV1 affects neural regeneration. In the present study, we established rat models of unilateral sciatic nerve crush injury, with or without pretreatment with AMG517（300 mg/kg）, a TRPV1 antagonist, injected subcutaneously into the ipsilateral paw 60 minutes before injury. At 1 and 2 weeks after injury, we performed immunofluorescence staining of the sciatic nerve at the center of injury, at 0.3 cm proximal and distal to the injury site, and in the dorsal root ganglia. Our results showed that Wallerian degeneration occurred distal to the injury site, and neurite outgrowth and Schwann cell regeneration occurred proximal to the injury. The number of regenerating myelinated and unmyelinated nerve clusters was greater in the AMG517-pretreated rats than in the vehicle-treated group, most notably 2 weeks after injury. TRPV1 expression in the injured sciatic nerve and ipsilateral dorsal root ganglia was markedly greater than on the contralateral side. Pretreatment with AMG517 blocked this effect. These data indicate that TRPV1 is activated or overexpressed after sciatic nerve crush injury, and that blockade of TRPV1 may accelerate regeneration of the injured sciatic nerve.展开更多
While the roles of glutamic acid （Glu）, arginine vasopressin （AVP） and their respective receptors in anxiety have been thoroughly investigated, the effects of interactions among Gila, N-methyl-D-aspartic acid （N...While the roles of glutamic acid （Glu）, arginine vasopressin （AVP） and their respective receptors in anxiety have been thoroughly investigated, the effects of interactions among Gila, N-methyl-D-aspartic acid （NMDA） receptor, AVP and a-amino-3- hydroxy-5-methylisoxazole-4-propionic acid （AMPA） receptor on anxiety are still unclear. In the present study, the agonist and antagonist of the NMDA receptor and AMPA receptor, as well as the antagonist of AVP V1 receptor （VlaR） were introduced into BALB/cJ mice by intracerebroventricular microinjection, and the anxiety-like behaviors of the mice were evaluated by open field and elevated plus-maze tests. Compared with C57BL/6 mice, BALB/cJ mice displayed higher levels of anxiety-like behavior. Significant anxiolytic effects were found in the NMDA receptor antagonist （MK-801） and the AMPA receptor or VlaR antagonist （SSRI49415）, as well as combinations of AVP/MK-801 and SSRI49415/DNQX. These results indicated that anxiety-like behaviors expressed in BALB/CJ mice may be due to a coordination disorder among glutamate, NMDA receptor, AMPA receptor, AVP and V1 aR, resulting in the up-regulation of the NMDA receptor and VlaR and down-regulation of the AMPA receptor. However, because the AMPA receptor can execute its anxiolytic function by suppressing AVP and VlaR, we cannot exclude the possibility of the NMDA receptor being activated by AVP acting on V1 aR.展开更多
Objective::This study was performed to investigate the effects of honokiol on the activation of transient receptor potential channel V1(TRPV1)and the secretion of thymic stromal lymphopoietin(TSLP)in a human benign ep...Objective::This study was performed to investigate the effects of honokiol on the activation of transient receptor potential channel V1(TRPV1)and the secretion of thymic stromal lymphopoietin(TSLP)in a human benign epidermal keratinocyte line(HaCaT).Methods::HaCaT keratinocytes were cultivated and divided into six groups:capsaicin-induced model control group,capsazepine control group,solvent control group,and three honokiol treatment groups(7.81,15.63,and 31.25 mg/L of honokiol).The effect of honokiol on calcium(Ca^(2+))influx was measured by a Ca^(2+)fluorescence imaging system.The fluorescence intensity(F)of cells was measured.The rate of change in F(ΔF/F0)was calculated,and theΔF/F0-time curve was constructed.HaCaT keratinocytes were stimulated with polyinosinic:polycytidylic acid,recombinant human tumor necrosis factorα,and recombinant human interleukin 4.Different concentrations of honokiol(15.63,7.81,and 3.91 mg/L)were added to the cells in the respective honokiol groups;20 mg/L of dexamethasone or 0.5%dimethyl sulfoxide was added to the cells in the positive control group or solvent control group.The TSLP concentration in the HaCaT keratinocytes of each group was detected by enzyme-linked immunosorbent assay.Statistical analysis was performed by one-way analysis of variance and Dunnett t test.Results::The capsaicin-induced Ca^(2+)fluorescence intensity in HaCaT keratinocytes was significantly inhibited in the 31.25 mg/L honokiol group;ΔF/F0 at 45 second was 0.76 in the model control group and 0 in the 31.25 mg/L honokiol group.The TSLP level in the 15.63 and 7.81 mg/L honokiol groups was lower than that in the solvent control group(t=7.382,P=0.003,and t=2.766,P=0.023,respectively),while the TSLP level in the 3.91 mg/L honokiol group was not significantly different from that in the solvent control group(t=1.872,P=0.124).Conclusions::Honokiol inhibited the Ca^(2+)influx induced by capsaicin(TRPV1 agonist)in HaCaT keratinocytes.Honokiol has an inhibitory effect on TSLP secretion in HaCaT keratinocytes.展开更多
Chronic inflammatory pain resulting from arthritis, nerve injury and tumor growth is a serious public health issue. One of the major challenges in chronic inflammatory pain research is to develop new pharmacologic tre...Chronic inflammatory pain resulting from arthritis, nerve injury and tumor growth is a serious public health issue. One of the major challenges in chronic inflammatory pain research is to develop new pharmacologic treatments with long-term efficacy and few side effects. The mediators released from inflamed sites induce complex changes in peripheral and central processing by directly acting on transducer receptors located on primary sensory neurons to transmit pain signals or indirectly modulating pain signals by activating receptors coupled with G-proteins and second messengers. High local proton concentration(acidosis) is thought to be a decisive factor in inflammatory pain and other mediators such as prostaglandin, bradykinin, and serotonin enhance proton-induced pain. Proton-sensing ion channels [transient receptor potential V1(TRPV1) and the acid-sensing ion channel(ASIC) family] are major receptors for direct excitation of nociceptive sensory neurons in response to acidosis or inflammation.G-protein-coupled receptors activated by prostaglandin, bradykinin, serotonin, and proton modulate functions of TRPV1, ASICs or other ion channels, thus leading to inflammation- or acidosis-linked hyperalgesia. Although detailed mechanisms remain unsolved, clearly different types of pain or hyperalgesia could be due to complex interactions between a distinct subset of inflammatory mediator receptors expressed in a subset of nociceptors. This review describes new directions for the development of novel therapeutic treatments in pain.展开更多
基金supported by the National Natural Science Foundation of China,No.81171178the Natural Science Foundation of Shanxi Province in China,No.2012011036-3Scientific Research Foundation of Shanxi Province of China for the Returned Overseas Chinese Scholars,No.2013011054-2
文摘The transient receptor potential cation channel subfamily V member 1（TRPV1） provides the sensation of pain（nociception）. However, it remains unknown whether TRPV1 is activated after peripheral nerve injury, or whether activation of TRPV1 affects neural regeneration. In the present study, we established rat models of unilateral sciatic nerve crush injury, with or without pretreatment with AMG517（300 mg/kg）, a TRPV1 antagonist, injected subcutaneously into the ipsilateral paw 60 minutes before injury. At 1 and 2 weeks after injury, we performed immunofluorescence staining of the sciatic nerve at the center of injury, at 0.3 cm proximal and distal to the injury site, and in the dorsal root ganglia. Our results showed that Wallerian degeneration occurred distal to the injury site, and neurite outgrowth and Schwann cell regeneration occurred proximal to the injury. The number of regenerating myelinated and unmyelinated nerve clusters was greater in the AMG517-pretreated rats than in the vehicle-treated group, most notably 2 weeks after injury. TRPV1 expression in the injured sciatic nerve and ipsilateral dorsal root ganglia was markedly greater than on the contralateral side. Pretreatment with AMG517 blocked this effect. These data indicate that TRPV1 is activated or overexpressed after sciatic nerve crush injury, and that blockade of TRPV1 may accelerate regeneration of the injured sciatic nerve.
基金This work was supported by the National Natural Science Foundation of China （31170377, 30970370） and the Fundamental Research Funds for Central University （GK201305009）
文摘While the roles of glutamic acid （Glu）, arginine vasopressin （AVP） and their respective receptors in anxiety have been thoroughly investigated, the effects of interactions among Gila, N-methyl-D-aspartic acid （NMDA） receptor, AVP and a-amino-3- hydroxy-5-methylisoxazole-4-propionic acid （AMPA） receptor on anxiety are still unclear. In the present study, the agonist and antagonist of the NMDA receptor and AMPA receptor, as well as the antagonist of AVP V1 receptor （VlaR） were introduced into BALB/cJ mice by intracerebroventricular microinjection, and the anxiety-like behaviors of the mice were evaluated by open field and elevated plus-maze tests. Compared with C57BL/6 mice, BALB/cJ mice displayed higher levels of anxiety-like behavior. Significant anxiolytic effects were found in the NMDA receptor antagonist （MK-801） and the AMPA receptor or VlaR antagonist （SSRI49415）, as well as combinations of AVP/MK-801 and SSRI49415/DNQX. These results indicated that anxiety-like behaviors expressed in BALB/CJ mice may be due to a coordination disorder among glutamate, NMDA receptor, AMPA receptor, AVP and V1 aR, resulting in the up-regulation of the NMDA receptor and VlaR and down-regulation of the AMPA receptor. However, because the AMPA receptor can execute its anxiolytic function by suppressing AVP and VlaR, we cannot exclude the possibility of the NMDA receptor being activated by AVP acting on V1 aR.
基金This work was supported by Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences(No.CAMS-2017-I2M-1-011).
文摘Objective::This study was performed to investigate the effects of honokiol on the activation of transient receptor potential channel V1(TRPV1)and the secretion of thymic stromal lymphopoietin(TSLP)in a human benign epidermal keratinocyte line(HaCaT).Methods::HaCaT keratinocytes were cultivated and divided into six groups:capsaicin-induced model control group,capsazepine control group,solvent control group,and three honokiol treatment groups(7.81,15.63,and 31.25 mg/L of honokiol).The effect of honokiol on calcium(Ca^(2+))influx was measured by a Ca^(2+)fluorescence imaging system.The fluorescence intensity(F)of cells was measured.The rate of change in F(ΔF/F0)was calculated,and theΔF/F0-time curve was constructed.HaCaT keratinocytes were stimulated with polyinosinic:polycytidylic acid,recombinant human tumor necrosis factorα,and recombinant human interleukin 4.Different concentrations of honokiol(15.63,7.81,and 3.91 mg/L)were added to the cells in the respective honokiol groups;20 mg/L of dexamethasone or 0.5%dimethyl sulfoxide was added to the cells in the positive control group or solvent control group.The TSLP concentration in the HaCaT keratinocytes of each group was detected by enzyme-linked immunosorbent assay.Statistical analysis was performed by one-way analysis of variance and Dunnett t test.Results::The capsaicin-induced Ca^(2+)fluorescence intensity in HaCaT keratinocytes was significantly inhibited in the 31.25 mg/L honokiol group;ΔF/F0 at 45 second was 0.76 in the model control group and 0 in the 31.25 mg/L honokiol group.The TSLP level in the 15.63 and 7.81 mg/L honokiol groups was lower than that in the solvent control group(t=7.382,P=0.003,and t=2.766,P=0.023,respectively),while the TSLP level in the 3.91 mg/L honokiol group was not significantly different from that in the solvent control group(t=1.872,P=0.124).Conclusions::Honokiol inhibited the Ca^(2+)influx induced by capsaicin(TRPV1 agonist)in HaCaT keratinocytes.Honokiol has an inhibitory effect on TSLP secretion in HaCaT keratinocytes.
基金Supported by(In part)Intramural Funding from Academia Sinicaby grants from the National Science Council,Taiwan(NSC 102-2325-B-001-042 to Chen CCNSC 101-2321-B-008-001 to Sun WH)
文摘Chronic inflammatory pain resulting from arthritis, nerve injury and tumor growth is a serious public health issue. One of the major challenges in chronic inflammatory pain research is to develop new pharmacologic treatments with long-term efficacy and few side effects. The mediators released from inflamed sites induce complex changes in peripheral and central processing by directly acting on transducer receptors located on primary sensory neurons to transmit pain signals or indirectly modulating pain signals by activating receptors coupled with G-proteins and second messengers. High local proton concentration(acidosis) is thought to be a decisive factor in inflammatory pain and other mediators such as prostaglandin, bradykinin, and serotonin enhance proton-induced pain. Proton-sensing ion channels [transient receptor potential V1(TRPV1) and the acid-sensing ion channel(ASIC) family] are major receptors for direct excitation of nociceptive sensory neurons in response to acidosis or inflammation.G-protein-coupled receptors activated by prostaglandin, bradykinin, serotonin, and proton modulate functions of TRPV1, ASICs or other ion channels, thus leading to inflammation- or acidosis-linked hyperalgesia. Although detailed mechanisms remain unsolved, clearly different types of pain or hyperalgesia could be due to complex interactions between a distinct subset of inflammatory mediator receptors expressed in a subset of nociceptors. This review describes new directions for the development of novel therapeutic treatments in pain.
