目的 观察电压依赖性钙通道是否作用于大鼠脊髓背角胶状质层（SG）神经元大振幅微小兴奋性突触后电流的形成。 方法 选用成年雄性Sprague-Dawley（SD）大鼠，2%～3%异氟烷麻醉后，分离其腰骶部的脊髓，然后切片。采用全细胞电压钳技术，玻璃微电极的电阻为4~6 MΩ，钳制电压为?70 mV，记录胶状质层神经元微小兴奋性突触后电流（mEPSC）电流。将电流信号用Axopatch 200来放大并储存于电脑。对照组和用药结束后，持续采样mEPSC电流30 s。mEPSC电流的频率和振幅用Clampfit 8.1进行分析。 结果 钳制电压为?70 mV时，所有SG神经元均有自发性的EPSC。辣椒素增加mEPSC发生的频率和波幅。钴离子抑制辣椒素诱导的大振幅mEPSC。钴离子抑制辣椒素诱导的mEPSC的平均振幅，而不抑制其发生频率。 结论 电压依赖性钙离子通道参与了辣椒素引起的痛觉形成。
【摘要】 目的 探讨辣椒素对不同年龄SD大鼠内脏感觉神经元上辣椒素受体（TRPV1）介导的离子通道的影响。 方法 急性分离7~9 d和21~23 d大鼠迷走神经结状神经节神经元，利用全细胞膜片钳技术在分离的神经元上记录辣椒素激活TRPV1受体后通道电流的变化。 结果 ①7~9 d和21~23 d大鼠内脏感觉神经元的膜电容分别为（18.57±8.60）和（19.85±9.47） pF，（Pgt;0.05）；②辣椒素能够激活7~9 d和21~23 d大鼠内脏感觉神经元上TRPV1并产生相似的内向电流，两组产生的峰电流密度分别为（48.59±18.87）、（55.91±20.52） pA/pF（Pgt;0.05）；③反复应用辣椒素使TRPV1受体发生失敏现象。 结论 大鼠内脏感觉神经元的TRPV1受体通道在出生后已经发育成熟，且对辣椒素激活的通道电流有相似的变化。【Abstract】 Objective To investigate the effects of capsaicin on transient receptor potential vanilloid 1 (TRPV1) receptor-mediated ion channel currents of visceral sensory neurons in different-aged Sprague-Dawley rats. Methods We isolated the vagal nodose ganglion neurons of rats at an age of 7-9 days or 21-23 days acutely. With the whole cell patch clamp technique, we recorded the current changes of TRPV1 channels activated by capsaicin. Results ① Membrane capacitances of the visceral sensory neurons were (18.57±8.60) and (19.85±9.47) pF in rats of 7-9 and 21-23 days, respectively (Pgt;0.05). ② Capsaicin activated the TRPV1 channels and generated inward currents in all the rats; and the peak current densities of the rats of 7-9 days and 21-23 days were respectively (48.59±18.87) and (55.91±20.52) pA/pF (Pgt;0.05). ③ Repeated applications of capsaicin produced a phenomenon of desensitization in TRPV1 channels. Conclusion TRPV1 receptor channels of visceral sensory neurons in rats have matured after birth, and the current changes of TRPV1 channels activated by capsaicin are similar.
【摘要】 目的 研究大剂量辣椒素对兔肺P物质和降钙素基因相关肽(CGRP)的影响。方法 将16只成年健康雄性新西兰大白兔随机分为两组:载体组(A)、大剂量辣椒素组(B)。两组动物取样前7 d和前6 d分别于颈部皮下注射等量的载体或者辣椒素(20 mg/mL)。大剂量戊巴比妥钠静脉麻醉处死动物后立即切取左肺下叶,称重,匀浆,离心后取上清液置于-80℃冰箱保存待测P物质和CGRP。结果 A组肺组织中P物质的浓度高于B组(Plt;0.05),而CGRP的浓度两组差异无统计学意义(P＞0.05)。结论 大剂量辣椒素(100 mg/kg)不能完全耗竭兔肺初级感觉神经纤维的神经肽类物质。
Objective Chronic cough is often present as increasing cough reaction to various physical and chemical stimulating factors. This study is aimed to investigate the difference of cough sensitivity and its mechanisms which are not clear among different causes of chronic cough. Methods Patients with chronic cough were recruited from cough clinic of Guangzhou Institute of Respiratory Diseases between 2005 to 2010. Using a modified diagnostic algorithm of chronic cough, common causes were identified. Capsaicin cough provocation test was also performed in these patients to assess the cough threshold. The relations between cough reflex sensitivity and duration of cough, cough severity, pulmonary function, induced sputum cell counts were then investigated. Results Through the diagnostic algorithm of chronic cough, the current study evaluated 133 adult patients, including 24 cases with upper airway cough syndrome (UACS) , 26 patients with cough variant asthma (CVA) , 31 cases with eosinophilic bronchitis (EB) , 30 patients with atopic cough (AC) , 22 cases with gastroesophageal reflux induced cough (GERC) . There were 30 healthy volunteers recruited as normal control. The cough threshold of LgC5 in AC, CVA, EB, GERC and UACS was 1.70 ±0.70, 2.12 ±0.67, 2.13 ±0.69, 1.69 ±0.73, 2.16 ±0.66, respectively. The LgC5 of the normal group ( 2.63 ±0.39) was higher than those in chronic cough groups( All P lt; 0.05) . The LgC5 of AC and GERC were lower than CVA, EB and UACS ( all Plt;0.05) . Duration and daytime score of cough showed positive correlations with LgC5( r =-0. 280, -0. 168, all P lt;0.05) . Pulmonary function and differential cell count of induced sputumwere not associated with LgC5 ( all Pgt;0.05) . Conclusions Different cause of chronic cough exhbit high cough reflex sensitivity to different extent. The difference of cough sensitivity may reflect the different pathogenesis among different causes, and may be related to the type of nerve fiber dominating the cough reflex.
The purpose of this study is to discuss the feasibility of establishing capsaicin pain model and the possibility to evaluate different degrees of pain by the heart rate variability (HRV). It also aims to investigate the changes of autonomic nervous activity of volunteers during the process of pain caused by capsaicin. A total of 30 volunteers were selected, who were physically and mentally healthy, into the study. To assess the effects of capsaicin on the healthy volunteers, we recorded the Visual Analogue Scale (VAS) scores after the capsaicin stimulus. Additionally, the electrocardiogram signals and HRV analysis index before and after stimulating were also recorded, respectively. More specifically, the HRV analysis indexes included the time domain index, the frequency domain index, and the nonlinear analysis index. The results demonstrated that the activity of the autonomic nerves was enhanced in the process of capsaicin stimulus, especially for the sympathetic nerve, which exhibited a significantly differences in HRV. In conclusion, the degree of pain can be reflected by the HRV. It is feasible to establish a capsaicin pain model. And in further experiments, HRV analysis could be used as a reference index for quantitative evaluation of pain.