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
Channel measurement and modeling is an important issue when designing ultra wideband (UWB) communication systems. A Precise model of the channel response is inevitable for designing an ultra wideband telecommunication...Channel measurement and modeling is an important issue when designing ultra wideband (UWB) communication systems. A Precise model of the channel response is inevitable for designing an ultra wideband telecommunication system. In this article signal propagation in indoor environment and LOS condition is evaluated and the appropriate model of this scenario is presented. Parameters such as the power delay profile, mean excess delay, delay spread, “NP10dB” are analyzed and simulated. Based on analysis results, the proposed model is presented. This model is based on Two-cluster approach but its average power delay profile is described with power function and cluster time of arrival is modeled by the modified exponential distribution. Finally UWB channel parameters of proposed model, Saleh and Valenzuela (S-V) and Two-cluster models are compared. Measurement and simulation results show that considerable improvement for mean excess delay, delay spread and “NP10dB” of proposed model comparing with S-V and Two-cluster model, this means the channel is better described, which mean the channel is described more precisely.展开更多
Although previous studies have shown the neuroprotective effects of the adenosine triphosphate （ATP）-sensitive potassium （KATP） channel opener against ischemic neuronal damage, little is known about the mechanisms...Although previous studies have shown the neuroprotective effects of the adenosine triphosphate （ATP）-sensitive potassium （KATP） channel opener against ischemic neuronal damage, little is known about the mechanisms involved. Phosphatidylinositol-3 kinase （PI3K）/v-akt murine thy-moma viral oncogene homolog （Akt） and Bcl-2 are thought to be important factors that mediate neuroprotection. The present study investigated the effects of KATP openers on hypoxia-induced PC12 cell apoptosis, as well as mRNA and protein expression of Akt and Bcl-2. Results demon-strated that pretreatment of PC12 cells with pinacidil, a KATP opener, resulted in decreased PC12 cell apoptosis following hypoxia, as detected by Annexin-V fluorescein isothiocyanate/ propidium iodide double staining flow cytometry. In addition, mRNA and protein expression of phosphorylated Akt （p-Akt） and Bcl-2 increased, as detected by immunofluorescence, Western blot analysis, and reverse-transcription polymerase chain reaction. The protective effect of this preconditioning was attenuated by glipizide, a selective KATP blocker. These results demonstrate for the first time that the protective mechanisms of KATP openers on PC12 cell apoptosis following hypoxia could result from activation of the PI3K/Akt signaling pathway, which further activates expression of the downstream Bcl-2 gene.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.
文摘Channel measurement and modeling is an important issue when designing ultra wideband (UWB) communication systems. A Precise model of the channel response is inevitable for designing an ultra wideband telecommunication system. In this article signal propagation in indoor environment and LOS condition is evaluated and the appropriate model of this scenario is presented. Parameters such as the power delay profile, mean excess delay, delay spread, “NP10dB” are analyzed and simulated. Based on analysis results, the proposed model is presented. This model is based on Two-cluster approach but its average power delay profile is described with power function and cluster time of arrival is modeled by the modified exponential distribution. Finally UWB channel parameters of proposed model, Saleh and Valenzuela (S-V) and Two-cluster models are compared. Measurement and simulation results show that considerable improvement for mean excess delay, delay spread and “NP10dB” of proposed model comparing with S-V and Two-cluster model, this means the channel is better described, which mean the channel is described more precisely.
基金the Natural Science Foundation of Liaoning Province,No.20052097,2008225010
文摘Although previous studies have shown the neuroprotective effects of the adenosine triphosphate （ATP）-sensitive potassium （KATP） channel opener against ischemic neuronal damage, little is known about the mechanisms involved. Phosphatidylinositol-3 kinase （PI3K）/v-akt murine thy-moma viral oncogene homolog （Akt） and Bcl-2 are thought to be important factors that mediate neuroprotection. The present study investigated the effects of KATP openers on hypoxia-induced PC12 cell apoptosis, as well as mRNA and protein expression of Akt and Bcl-2. Results demon-strated that pretreatment of PC12 cells with pinacidil, a KATP opener, resulted in decreased PC12 cell apoptosis following hypoxia, as detected by Annexin-V fluorescein isothiocyanate/ propidium iodide double staining flow cytometry. In addition, mRNA and protein expression of phosphorylated Akt （p-Akt） and Bcl-2 increased, as detected by immunofluorescence, Western blot analysis, and reverse-transcription polymerase chain reaction. The protective effect of this preconditioning was attenuated by glipizide, a selective KATP blocker. These results demonstrate for the first time that the protective mechanisms of KATP openers on PC12 cell apoptosis following hypoxia could result from activation of the PI3K/Akt signaling pathway, which further activates expression of the downstream Bcl-2 gene.
