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Objectives: To examine the effect of intrathecal (i.t.) serotonin (5‐hydroxytryptamine) 5‐HT7 agonist administration on voiding function in the urethane‐anesthetised rat, and the change in 5‐HT7 receptor (5‐HT7R) expression in the lumbosacral cord Onuf's nucleus after spinal cord injury (SCI). Materials and methods: In all, 32 female Sprague–Dawley (SD) rats were equally divided into a spinally intact (SI) group and SCI group (n = 16 each). At 8 weeks after transection, half of the rats underwent continuous cystometry under urethane anaesthesia, and the 5‐HT7R‐selective agonist LP44 was given (i.t.). The remaining rats were used for pseudorabies (PRV) retrograde tracing, immunofluorescence, and Western Blot. Results: LP44 administered i.t. had no effect in the SI rats. In SCI rats, LP44 (1–30 μg/kg) induced significant dose‐dependent increases in micturition volume, voiding efficiency, number of high‐frequency oscillations per micturition; and decreases in residual volume, bladder capacity, peak bladder pressure, threshold pressure and non‐voiding contractions. The 5‐HT7R antagonist, SB‐269970 (10 μg/kg), partially reversed LP44‐induced changes. Using PRV retrograde tracing and immunofluorescence, 5‐HT7Rs were found in the L6–S1 spinal cord Onuf's nucleus in both SI and SCI rats, but the expression was significantly greater in the SCI rats. Western blot showed significantly more 5‐HT7Rs in the ventral L6–S1 spinal cord in SCI rats. Conclusion: A 5‐HT7R agonist, given i.t., improved voiding efficiency in urethane‐anesthetised SCI rats, and the 5‐HT7R was significantly up‐regulated in the lumbosacral cord Onuf's nucleus. If valid for humans, these findings suggest that the 5‐HT7R could be a target for therapeutic interventions. [ABSTRACT FROM AUTHOR]

Aim: To investigate the value of repeat botulinum toxin A (BTX‐A) injections in patients with neurogenic detrusor overactivity (NDO). Methods: We searched the PubMed, EMBASE, and EBSCO databases for articles published until June 2016. Studies that reported the efficacy and safety of repeat BTX‐A injections for adult patients with NDO were eligible. The effect size for each outcome was calculated as the standardized mean difference ± standard error and 95% confidence interval, and was graded as small, >0.2; moderate, >0.5; or large, >0.8. The outcomes included maximum cystometric capacity (MCC), maximum detrusor pressure (MDP), reflex volume (RV), bladder compliance (BC), quality of life (QOL), and injection interval. Descriptive reviews were performed for urinary incontinence (UI) and adverse events (AEs). Results: Eighteen studies involving 1533 patients whose level of evidence ranged from 3 to 4 were included in this study. We noted non‐significant changes in MCC, MDP, RV, and BC between the first and last injections. Patients who had received ≤4 injections were found to have stable QOL improvements after the first and last injections, whereas patients who had received ≥5 injections were found to have a significant decrease in QOL after the last injection. No significant differences in injection intervals were noted after repeat BTX‐A injections, and the repeat injection failure rate was low. Conclusion: Our study demonstrated that repeat BTX‐A injections allow sustained improvements in patients with NDO. The rate of AEs was stable and low. However, additional high‐quality, large‐scale, and long‐term trials are necessary to establish the efficacy and safety of ≥5 repeat BTX‐A injections. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether the voiding dysfunction caused by spinal cord injury (SCI) in rats can be improved by i.v. administration of the serotonin (5‐HT)2A/2C receptor agonist 2,5‐dimethoxy‐4‐iodophenyl‐2‐aminopropanehydrochloride (DOI), and to discuss whether the mechanism can be ascribed to 5‐HT2A and 5‐HT 2C receptor upregulation in lumbosacral cord motoneurons. Materials and Methods: Female Sprague–Dawley rats were divided into two groups (SCI group vs normal control [NC] group). Under urethane anaesthesia, cystometry was performed to examine the variation in urodynamic variables before and after successive intrathecal (i.t.) administration of various doses of DOI into the lumbosacral cord. Changes in 5‐HT2A and ‐2C receptors in the lumbosacral cord were also investigated using immunohistochemical staining and Western blot analysis. Results: Compared with NC rats, the SCI rats had higher bladder capacity and post‐void residual urine volume, and lower voiding efficiency. After SCI, DOI improved voiding efficiency, probably via external urethral sphincter (EUS) activity. Immunohistochemical staining and Western blot analysis showed that 5‐HT2A and ‐2C receptors were upregulated in lumbosacral cord motoneurons. Conclusion: In rats with SCI, DOI can improve voiding efficiency; this may be attributable to 5‐HT2A and ‐2C receptor upregulation in lumbosacral cord motoneurons controlling EUS activity. [ABSTRACT FROM AUTHOR]

To investigate the effect of nerve growth factor (NGF) neutralization on Na+ channel plasticity of bladder afferent neurons in mice with spinal cord injury (SCI). Female C57/BL6 mice were randomly divided into spinal intact (SI) group, SCI group and SCI + NGF-Ab group. SCI was induced by spinal cord transection at the Th8/9 level. In SCI + NGF-Ab group, anti-NGF antibodies (10 μg·kg-1 per hour) were continuously administered for 2 weeks using osmotic pumps. Bladder afferent neurons were labelled with Fluoro‑gold (FG) injected into the bladder wall. L6-S1 dorsal root ganglion (DRG) neurons were dissociated and whole-cell patch clamp recordings were performed on FG-labelled neurons. Expression of Nav1.7 and Nav1.8 was examined by immunofluorescent staining. Whole-cell patch clamp recordings showed that TTX only partially inhibited action potentials (AP) and Na+ currents of bladder afferent neurons in SI mice, but it almost completely inhibited them in SCI mice. Total and TTX-sensitive Na+ currents were increased and TTX-resistant currents were decreased in bladder afferent neurons from SCI mice vs. SI mice. These changes in SCI mice were significantly reversed by NGF-antibody treatment. Immunostaining results showed the increased and decreased levels of Nav1.7 and Nav1.8, respectively, in FG-labelled bladder afferent neurons in SCI mice vs. SI mice, which was significantly reversed in SCI + NGF-Ab mice. NGF mediates the Na+ channel plasticity with a shift from TTX-resistant Nav1.8 to TTX-sensitive Nav1.7 in bladder afferent neurons, which could be a possible underlying mechanism of bladder afferent hyperexcitability and detrusor overactivity after SCI. [ABSTRACT FROM AUTHOR]

Nerve growth factor (NGF) has been implicated as a key molecule of pathology-induced changes in C-fiber afferent nerve excitability, which contributes to the emergence of neurogenic detrusor overactivity due to spinal cord injury (SCI). It is also known that the second messenger signaling pathways activated by NGF utilize p38 Mitogen-Activated Protein Kinase (MAPK). We examined the roles of p38 MAPK on electrophysiological properties of capsaicin sensitive bladder afferent neurons with SCI mice. We used female C57BL/6 mice and transected their spinal cord at the Th8/9 level. Two weeks later, continuous administration of p38 MAPK inhibitor (0.51 μg/h, i.t. for two weeks) was started. Bladder afferent neurons were labelled with a fluorescent retrograde tracer, Fast-Blue (FB), injected into the bladder wall three weeks after SCI. Four weeks after SCI, freshly dissociated L6-S1 dorsal root ganglion neurons were prepared and whole cell patch clamp recordings were performed in FB-labelled neurons. After recording action potentials or voltage-gated K+ currents, the sensitivity of each neuron to capsaicin was evaluated. In capsaicin-sensitive FB-labelled neurons, SCI significantly reduced the spike threshold and increased the number of action potentials during 800 ms membrane depolarization. Densities of slow-decaying A-type K+ (K A) and sustained delayed rectifier-type K+ (K DR) currents were significantly reduced by SCI. The reduction of K A , but not K DR , current density was reversed by the treatment with p38 MAPK inhibitor. P38 MAPK plays an important role in hyperexcitability of capsaicin-sensitive bladder afferent neurons due to the reduction in K A channel activity in SCI mice. [ABSTRACT FROM AUTHOR]