The role of 5-HT2 receptor subtypes in the control of micturition in urethane anaesthetized female rats.

Central 5-HT containing pathways have been shown to play an important role in the control of micturition with a focus on 5-HT receptor influence on the parasympathetic outflow to the bladder, and somatic outflow to the external urethral sphincter (EUS) in the rat. 5-HTjA and 5-HT7 receptors have been revealed to be physiologically involved in the control of micturition. Moreover, from the literature, activation of the 5-HT2 receptor, specifically 5-HT2C receptor has been observed to be inhibitory on the micturition reflex, although no physiological role for this receptor subtype has yet been established. Using reportedly selective 5-HT2 receptor agonists and antagonists, the present work reveals the excitatory actions of the 5-HT2A receptor on the external urethral sphincter and the micturition reflex, the inhibitory actions of the 5-HT2C receptor in micturition and the involvement of 5-HT2B receptors in mediating urethral smooth muscle contraction. Further, data from the present study demonstrates that 5-HT2A receptors excite the external urethral sphincter at the level of the sacral spinal cord and further supports the view that the inhibitory action of the 5-HT2C receptors on micturition is centrally mediated. Molecular evidence regarding expression of 5-HT2 receptor subtypes in the lower urinary tract of the rat is also provided in the present study, with 5-HT2A, 5- HT2B and 5-HT2C receptor mRNA expression observed in the rat bladder, urethra and brain respectively. Overall, this thesis provides evidence for the involvement of 5-HT2 receptors in the control of micturition, although it is still unclear as to the physiological role of this receptor family in the control of micturition

Schwarzinicine A inhibits transient receptor potential canonical channels and exhibits overt vasorelaxation effects

This study investigated the vasorelaxant effects of schwarzinicine A, an alkaloid recently reported from Ficus schwarzii Koord. Regulation of calcium homeostasis in vascular smooth muscle cells (VSMC) is viewed as one of the main mechanisms for controlling blood pressure. L-type voltage-gated calcium channel (VGCC) blockers are commonly used for controlling hypertension. Recently, the transient receptor potential canonical (TRPC) channels were found in blood vessels of different animal species with evidence of their roles in the regulation of vascular contractility. In this study, we studied the mechanism of actions of schwarzinicine A focusing on its regulation of L-type VGCC and TRPC channels. Schwarzinicine A exhibited the highest vasorelaxant effect (123.1%) compared to other calcium channel blockers. It also overtly attenuated calcium-induced contractions of the rat isolated aortae in a calcium-free environment showing its mechanism to inhibit calcium influx. Fluorometric intracellular calcium recordings confirmed its inhibition of hTRPC3-, hTRPC4-, hTRPC5- and hTRPC6-mediated calcium influx into HEK cells with IC50 values of 3, 17, 19 and 7 μM, respectively. The evidence gathered in this study suggests that schwarzinicine A blocks multiple TRPC channels and L-type VGCC to exert a significant vascular relaxation response

Effects of cannabinoid receptor activation by CP55,940 on normal bladder function and irritation-induced bladder overactivity in non-awake anaesthetised rats.

INTRODUCTION AND HYPOTHESIS: This study was designed to evaluate the effects of CP55,940 on normal bladder function in vivo and examine whether it suppresses urinary frequency induced by nociceptive stimuli in the bladder. Cannabinoid receptor (CBR) activity may be involved in the regulation of bladder function. However, the role of CBR subtypes in micturition has yet to be established. CP55,940 is a synthetic analogue of tetrahydrocannabidiol, which is a psychoactive ingredient of the Cannabis plant. METHODS: Cystometry under urethane anaesthesia was performed to evaluate the effect of intravesical delivery of CP55,940 with or without administration of CB1 antagonist AM251 or CB2 antagonist AM630 on bladder function in female rats. The effects of CP55,940 were also examined in rats with urinary irritation induced by intravesical infusion of acetic acid. RESULTS: Infusion of CP55,940 significantly (p < 0.05) increased micturition interval (MI) and bladder capacity (BC) by 52 % and decreased maximal voiding pressure (MP) by 25 %. Pretreatment with AM251 or AM630 before CP55,940 administration prevented CP55,940-induced increases in MI, BC and reduced MP. Acetic acid induced urinary frequency as evidenced by a reduction in MI and was suppressed by CP55,940. CONCLUSIONS: CP55,940 decreases bladder activity and urinary frequency induced by nociceptive stimuli, probably by suppression of bladder afferent activity. Effects of CP55,940 were abolished by both CBR antagonists. This data implicates a role for the endocannabinoid system in bladder mechanoafferent function in rats. In addition, our results show that CP55,940 reverses urinary frequency exemplified in an overactive bladder model, suggesting it could be an effective treatment for patients with lower urinary tract symptoms

Neural control of the female urethral and anal rhabdosphincters and pelvic floor muscles

The urethral rhabdosphincter and pelvic floor muscles are important in maintenance of urinary continence and in preventing descent of pelvic organs [i.e., pelvic organ prolapse (POP)]. Despite its clinical importance and complexity, a comprehensive review of neural control of the rhabdosphincter and pelvic floor muscles is lacking. The present review places historical and recent basic science findings on neural control into the context of functional anatomy of the pelvic muscles and their coordination with visceral function and correlates basic science findings with clinical findings when possible. This review briefly describes the striated muscles of the pelvis and then provides details on the peripheral innervation and, in particular, the contributions of the pudendal and levator ani nerves to the function of the various pelvic muscles. The locations and unique phenotypic characteristics of rhabdosphincter motor neurons located in Onuf's nucleus, and levator ani motor neurons located diffusely in the sacral ventral horn, are provided along with the locations and phenotypes of primary afferent neurons that convey sensory information from these muscles. Spinal and supraspinal pathways mediating excitatory and inhibitory inputs to the motor neurons are described; the relative contributions of the nerves to urethral function and their involvement in POP and incontinence are discussed. Finally, a detailed summary of the neurochemical anatomy of Onuf's nucleus and the pharmacological control of the rhabdosphincter are provided

RNA-Seq-based analysis of the physiologic cold shock-induced changes in Moraxella catarrhalis gene expression

BACKGROUND: Moraxella catarrhalis, a major nasopharyngeal pathogen of the human respiratory tract, is exposed to rapid downshifts of environmental temperature when humans breathe cold air. The prevalence of pharyngeal colonization and respiratory tract infections caused by M. catarrhalis is greatest in winter. We investigated how M. catarrhalis uses the physiologic exposure to cold air to regulate pivotal survival systems that may contribute to M. catarrhalis virulence. RESULTS: In this study we used the RNA-seq techniques to quantitatively catalogue the transcriptome of M. catarrhalis exposed to a 26 °C cold shock or to continuous growth at 37 °C. Validation of RNA-seq data using quantitative RT-PCR analysis demonstrated the RNA-seq results to be highly reliable. We observed that a 26 °C cold shock induces the expression of genes that in other bacteria have been related to virulence a strong induction was observed for genes involved in high affinity phosphate transport and iron acquisition, indicating that M. catarrhalis makes a better use of both phosphate and iron resources after exposure to cold shock. We detected the induction of genes involved in nitrogen metabolism, as well as several outer membrane proteins, including ompA, m35-like porin and multidrug efflux pump (acrAB) indicating that M. catarrhalis remodels its membrane components in response to downshift of temperature. Furthermore, we demonstrate that a 26 °C cold shock enhances the induction of genes encoding the type IV pili that are essential for natural transformation, and increases the genetic competence of M. catarrhalis, which may facilitate the rapid spread and acquisition of novel virulence-associated genes. CONCLUSION: Cold shock at a physiologically relevant temperature of 26 °C induces in M. catarrhalis a complex of adaptive mechanisms that could convey novel pathogenic functions and may contribute to enhanced colonization and virulence

Expression of 5-Hydroxytryptamine Receptors in Human Urinary Bladders with Benign Prostatic Hyperplasia

Introduction: This study investigated the mRNA expression pattern and distribution of 5-hydroxytryptamine (5-HT) receptors 5-HT2A, 5-HT2B, 5-HT3A, 5-HT4, and 5-HT7 within the urothelium and detrusor of normal bladder tissue and in the urothelium of bladders from patients with benign prostatic hyperplasia (BPH). Methods: Normal urinary bladder specimens were obtained from 13 patients undergoing radical cystectomy due to bladder cancer (normal group) and BPH specimens were obtained from 27 benign prostatic obstruction patients receiving transurethral prostatectomy or retropubic prostatectomy. Receptor subtype mRNA expression was determined by real-time reverse transcription polymerase chain reaction on urothelium, detrusor, and whole mucosal preparations. Receptor distribution was determined by immunohistochemistry. Results: In normal tissues, expressions of 5-HT2B and 5-HT7 receptor mRNAs in the urothelium, detrusor, and whole mucosa were greater than the average expression for all receptor subtype mRNAs. 5-HT2B receptor protein was distributed in the apical urothelium and among the detrusor smooth muscle layers. In contrast, the 5-HT7 receptors were within the urothelium middle cell layers and detrusor smooth muscle cells. The expression pattern of each 5-HT receptor subtype mRNA within the BPH urothelium was similar to that in the normal urothelium. The expression level of 5-HT2A receptor mRNA in the BPH group was significantly lower than the normal group; however, the expressions of both 5-HT3A and 5-HT7 mRNAs were significantly higher. The expressions of both 5-HT2B and 5-HT4 mRNAs were not significantly different between the normal and BPH groups. Conclusion: In normal urinary bladders, the expressions of both 5-HT2B and 5-HT7 mRNAs were higher compared to the 5-HT2A, 5-HT3A, and 5-HT4 mRNAs. The distributions of 5-HT2B and 5-HT7 receptors were different in the urothelium and detrusor layers. The 5-HT3A and 5-HT7 receptor mRNAs in the BPH group were significantly higher compared to the normal urothelium, while the 5-HT2A mRNA was significantly lower.ArticleADVANCES IN THERAPY.32:S29-S37(2015)journal articl