Colonic inflammation up-regulates voltage-gated sodium channels in bladder sensory neurons via activation of peripheral transient potential vanilloid 1 receptors

Background Primary sensory neurons express several types of ion channels including transient receptor potential vanilloid 1 (TRPV1) and voltage‐gated Na⁺ channels. Our previous studies showed an increased excitability of bladder primary sensory and spinal neurons triggered by inflammation in the distal colon as a result of pelvic organ cross‐sensitization. The goal of this work was to determine the effects of TRPV1 receptor activation by potent agonists and/or colonic inflammation on voltage‐gated Na⁺ channels expressed in bladder sensory neurons. Methods Sprague–Dawley rats were treated with intracolonic saline (control), resiniferatoxin (RTX, 10^?7 mol L^?1), TNBS (colonic irritant) or double treatment (RTX followed by TNBS). Key Results TNBS‐induced colitis increased the amplitude of total Na⁺ current by two‐fold and of tetrodotoxin resistant (TTX‐R) Na⁺ current by 78% (P ≤ 0.05 to control) in lumbosacral bladder neurons during acute phase (3 days post‐TNBS). Instillation of RTX in the distal colon caused an enhancement in the amplitude of total Na⁺ current at ?20 mV from ?112.1 ± 18.7 pA/pF (control) to ?183.6 ± 27.8 pA/pF (3 days post‐RTX, P ≤ 0.05) without changes in TTX resistant component. The amplitude of net Na⁺ current was also increased by 119% at day 3 in the group with double treatment (RTX followed by TNBS, P ≤ 0.05 to control) which was significantly higher than in either group with a single treatment. Conclusions & Inferences These results provide evidence that colonic inflammation activates TRPV1 receptors at the peripheral sensory terminals leading to an up‐regulation of voltage gated Na⁺ channels on the cell soma of bladder sensory neurons. This mechanism may underlie the occurrence of peripheral cross‐sensitization in the pelvis and functional chronic pelvic pain.     

DRGs付费制度实施难点问题探讨

结合工作实际,根据《国家医疗保障DRG分组与付费技术规范》和《国家医疗保障DRG(CHS-DRG)分组方案》,探讨了DRGs在实施过程中遇到的难点,并针对性地提出相关建议,以供试点城市和医疗机构参考。     

Anatomical and cytochemical relationships of adenosine deaminase-containing primary afferent neurons in the rat

The distribution of adenosine deaminase-containing neurons and fibers in the spinal cord and medulla was examined and the relationship of dorsal root ganglia neurons containing this enzyme to those containing somatostatin, substance P, fluoride-resistant acid phosphatase (FRAP) and 5'-nucleotidase was determined using immunohistochemical and histochemical methods. In the spinal cord adenosine deaminase-immunoreactive fibers and neurons were confined to layer I and IIo. A similar localization of these was observed in the spinal trigeminal nucleus. In adult animals treated neonatally with capsaicin adenosine deaminase-positive fibers were totally depleted in layer IIo but only partially depleted in layer I. Analysis of lumbar sensory ganglia revealed that small type-B neurons immunoreactive for adenosine deaminase were also immunoreactive for somatostatin but not substance P. In addition, adenosine deaminase-positive neurons lacked histochemical reaction-product for FRAP and exhibited the lowest activity of 5'-nucleotidase. Examination of the neuronal populations containing the two phosphatase enzymes showed that a proportion of neurons exhibiting 5'-nucleotidase activity were devoid of FRAP activity. It is concluded that dorsal root ganglia neurons immunoreactive for adenosine deaminase and somatostatin constitute a single subpopulation of type-B ganglion cells separate from those containing substance P or FRAP. It appears that the lack of coexistence of adenosine deaminase with either FRAP or 5'-nucleotidase cannot be attributed simply to a coexistence of the two latter enzymes since some 5'-nucleotidase-positive neurons lacking FRAP were also devoid of adenosine deaminase-immunoreactivity. Insofar as these three enzymes may contribute to the regulation of transmission processes in primary sensory neurons, our results indicate a minimal functional relationship between adenine nucleoside and nucleotide degrading enzymes in these neurons. In addition, FRAP appears to have some functional independence from 5'-nucleotidase.     

Nanomolar ambient ATP decelerates P2X3 receptor kinetics

Homomeric P2X receptors differ in their electrophysiological and pharmacological profiles. The rapidly activating and desensitizing P2X₃ receptors are known for their involvement in pain signalling pathways. Modulatory effects on P2X₃ receptors have been reported for low concentrations of ATP ([ATP]). This includes both, enhancement and reduction of receptor currents. The first has been reported to be mediated by activation of ectoprotein kinases and high affinity desensitization (HAD), respectively. Both processes influence receptor current amplitudes. Here we describe a new phenomenon, the modulatory influence of ambient low [ATP] on P2X₃ receptor kinetics. First, we studied in HEK cells whether persistent ATP affects current decay. To this end, P2X₃ receptor mediated currents, elicited by pressure application of saturating [ATP], were analyzed after pre-application of low [ATP]. Second, UV-flash photolysis of ATP was employed to investigate whether submicromolar [ATP] affects receptor activation. Finally we confirmed the action of nanomolar [ATP] on native P2X₃ receptors of neurons freshly isolated from rat dorsal root ganglia. We found that persistent low [ATP] caused pronounced deceleration of receptor current activation and decay. This priming effect indicates a mechanism different from HAD. It could be explained by a pre-opening receptor isomerization, induced by the occupation of a high affinity binding site already at the resting state. The observed modulation of the receptor kinetics could be considered as a physiological fine tuning mechanism of the nociceptive system, driven by the actual ambient agonist concentration.     

Uracil nucleotides: from metabolic intermediates to neuroprotection and neuroinflammation

Uracil nucleotides (i.e., UTP and UDP) have been known for years as fundamental intermediates in the de novo synthesis of the other pyrimidine nucleotides, which altogether represent key building blocks for nucleic acid synthesis. In addition, their sugar conjugates (i.e., UDP-glucose and UDP-galactose) enter in several biochemical routes, for example leading to glycogen biosynthesis, and protein and lipid glycosylation, which in turn contribute to the synthesis of essential components of the cellular plasma membrane. More recently, the existence of a "pyrimidinergic transmission" has arisen from the discovery that several purinergic G protein-coupled P2Y receptors can be activated also or exclusively by uracil nucleotides and sugar conjugates. The number of these receptors is continuously growing over years with the discovery that previously "orphan" G protein-coupled receptors are actually responding to this class of molecules. Therefore, new unforeseen effects mediated by uracil derivatives have emerged, in particular in the nervous system, and previously unexplored avenues for the pharmacological manipulation of this system are currently under investigation. In this commentary we shall try to put together our current knowledge on the biochemical and receptor-mediated effects of uracil nucleotide derivatives with a specific focus on the nervous system in order to depict a clearer view of the importance of the pyrimidinergic system in both physiological and pathological conditions.     

Jingzhaotoxin-II, a novel tarantula toxin preferentially targets rat cardiac sodium channel

Naturally occurring toxins are invaluable tools for exploration of the structure and function relationships of voltage-gated sodium channels (VGSCs). In this study, we isolated and characterized a novel VGSC toxin named jingzhaotoxin-II (JZTX-II) from the tarantula Chilobrachys jingzhao venom. JZTX-II consists of 32 amino acid residues including two acidic and two basic residues. Cloned and sequenced using 3'- and 5'-rapid amplification of the cDNA ends, the full-length cDNA for JZTX-II was found to encode a 63-residue precursor which contained a signal peptide of 21 residues, a propeptide of 10 residues and a mature peptide of 32 residues. Under whole-cell voltage-clamp conditions, JZTX-II significantly slowed rapid inactivation of TTX-resistant (TTX-R) VGSC on cardiac myocytes with the IC50=0.26+/-0.09 microM. In addition, JZTX-II had no effect on TTX-R VGSCs on rat dorsal root ganglion neurons but exerted a concentration-dependent reduction in tetrodotoxin-sensitive (TTX-S) VGSCs accompanied by a slowing of sodium current inactivation similar to delta-ACTXs. It is notable that TTX-S VGSCs on cultured rat hippocampal neurons were resistant to JZTX-II at high dose. Based on its high selectivity for mammalian VGSC subtypes, JZTX-II might be an important ligand for discrimination of VGSC subtypes and for exploration of the distribution and modulation mechanisms of VGSCs.     

新生儿出生体重与入院体重对DRG分组影响分析

目的 为提升新生儿DRG分组的准确性,分别应用出生体重与入院体重作为入组条件,寻找入组依据。方法 数据来源于某市2016年1月1日-2020年12月31日出生天数<29 d的新生儿病案首页数据,应用CN-DRG分组方案(2018版)进行DRG分组,采用SPSS 24.0软件进行统计分析。结果 新生儿出生体重与入院体重均完整者占新生儿首页数据的77.1%;对于新生儿体重密切相关DRG组别,将出生体重与入院体重分别作为入组条件,入组一致及差异分别占97.6%及2.4%;对于入组存在差异的1 821例,按照出生体重与入院体重入组准确分别占83.1%及8.5%,新生儿平均出生天数分别为6.00 d、18.85 d;对于新生儿平均出生天数≤7 d按出生体重入组准确,平均出生天数>14 d按出生天数构成及伴随问题选择入组体重;新生儿出生天数为8 d～14 d,出生体重与入院体重入组无差异。线性回归分析显示,出生体重回归系数绝对值>入院体重回归系数绝对值。结论 新生儿出生体重对DRG分组影响大于入院体重。应关注早产儿出生体重与入院体重变化,提升病案首页新生儿出生体重与入院体重的完整...     

质粒型单纯疱疹病毒载体介导GDNF和GFP基因在体外培养的BHK细胞和大鼠脊髓、背根节神经元中的转移和表达

为了观察质粒型单纯疱疹病毒载体介导的外源性胶质细胞源性神经营养因子和绿色荧光蛋白基因在体外培养的金黄地鼠肾细胞以及脊髓神经元和背根节神经元中的转移和表达 ,本研究采用了以质粒型单纯疱疹病毒载体为基础构建的分别含有重组胶质细胞源性神经营养因子和绿色荧光蛋白基因的混合毒株 dv HSV-GDNF和 dv HSV-GFP感染体外培养的金黄地鼠肾细胞、脊髓神经元和背根节神经元。用免疫组织化学方法和荧光显微镜观测法分别检测了胶质细胞源性神经营养因子和绿色荧光蛋白基因的转移和表达。结果发现 :质粒型单纯疱疹病毒载体可以成功地将外源性胶质细胞源性神经营养因子和绿色荧光蛋白基因导入金黄地鼠的肾细胞以及脊髓神经元和背根节神经元中。提示质粒型单纯疱疹病毒载体可以作为转基因胶质细胞源性营养因子治疗脊髓损伤的转移载体 ,为脊髓损伤的基因治疗提供了实验基础。绿色荧光蛋白作为报告基因 ,也可因其适用广泛、观察简便等特性而得到更加广泛的应用。     

Fatty acid binding protein is induced in neurons of the dorsal root ganglia after peripheral nerve injury

Peripheral nerve trauma induces the expression of genes presumed to be involved in the process of nerve degeneration and repair. In the present study, an in vivo paradigm was employed to identify molecules which may have important roles in these processes. A cDNA library was constructed with RNA extracted from rat dorsal root ganglia (DRG) 3 days after a sciatic nerve crush. After differential hybridization to this library, several cDNAs were identified that encoded mRNAs that were upregulated in the DRG ipsilateral to the crush injury, as opposed to the contralateral or naive DRG. Approximately 0.15% of all the clones screened were found to be induced. This report presents the types of induced sequences identified and characterizes one of them, DA11. The 0.7 kb DA11 full length cDNA clone contains a 405 nucleotide open reading frame that encodes a putative protein of 15.2 kDa (135 amino acid residues) and is a member of the family of fatty acid binding proteins (FABP). The DA11 protein differs by one amino acid residue from the sequence of the C-FAPB protein and by eight residues from the sequence of mal1, proteins found in rat and mouse skin, respectively. Northern and Western blot analyses showed that the DA11 mRNA and protein were induced in the injured DRG. Furthermore, studies using antibodies generated against DA11 found that the DA11-like immunoreactivity was more pronounced in the nuclei of neurons located in the DRG ipsilateral to the sciatic cut than those located in the contralateral DRG. The induction of DA11 mRNA and protein in DRG neurons suggests, for the first time, the involvement of a neuronal FABP in the process of degeneration and repair in the nervous system. © 1996 Wiley-Liss, Inc.     

Optogenetically enhanced axon regeneration: motor versus sensory neuron‐specific stimulation

Brief neuronal activation in injured peripheral nerves is both necessary and sufficient to enhance motor axon regeneration, and this effect is specific to the activated motoneurons. It is less clear whether sensory neurons respond in a similar manner to neuronal activation following peripheral axotomy. Further, it is unknown to what extent enhancement of axon regeneration with increased neuronal activity relies on a reflexive interaction within the spinal circuitry. We used mouse genetics and optical tools to evaluate the precision and selectivity of system‐specific neuronal activation to enhance axon regeneration in a mixed nerve. We evaluated sensory and motor axon regeneration in two different mouse models expressing the light‐sensitive cation channel, channelrhodopsin (ChR2). We selectively activated either sensory or motor axons using light stimulation combined with transection and repair of the sciatic nerve. Regardless of genotype, the number of ChR2‐positive neurons whose axons had regenerated successfully was greater following system‐specific optical treatment, with no effect on the number of ChR2‐negative neurons (whether motor or sensory neurons). We conclude that acute system‐specific neuronal activation is sufficient to enhance both motor and sensory axon regeneration. This regeneration‐enhancing effect is likely cell autonomous.