Intravesical Infusion Of Acetic Acid Research Articles

Netupitant, a Potent and Highly Selective NK1 Receptor Antagonist, Alleviates Acetic Acid-Induced Bladder Overactivity in Anesthetized Guinea-Pigs.

Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA).Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of AA. After a 30 min stabilization period, netupitant (0.1–3 mg/kg, i.v.) or L-733,060 (3–10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM.Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex circuit and therefore may be useful clinically in treating bladder overactivity symptoms.

Differences in neurotransmitter systems of ventrolateral periaqueductal gray between the micturition reflex and nociceptive regulation: An in vivo microdialysis study.

To elucidate the possible involvement of glutamate and serotonin (5-hydroxytryptamine) neurons in the ventrolateral midbrain periaqueductal gray during noxious stimulation. The study was carried out by evoking a noxious stimulation by acetic acid in an animal model of cystitis. Changes in glutamate and 5-hydroxytryptamine in the periaqueductal gray during the micturition reflex and acetic acid-induced cystitis were determined using in vivo microdialysis combined with cystometry in rats. Extracellular glutamate levels slightly, but significantly, increased during the micturition reflex induced by saline infusion into the bladder. Intravesical infusion of acetic acid facilitated the micturition reflex characterized by increases in voiding pressure and decreases in the intercontraction interval. Glutamate levels were markedly increased by acetic acid, and this enhancement was sustained for at least 3 h. 5-Hydroxytryptamine levels, which were not altered during the micturition reflex, were increased after intravesical infusion of acetic acid. The results suggest that periaqueductal gray glutamate and 5-hydroxytryptamine neurons differentially participate in the modulation of both nociception and the micturition reflex. Furthermore, periaqueductal gray 5-hydroxytryptamine levels appear to reflect the nociceptive stimuli.

Optimization of Neuromodulation for Bladder Control in a Rat Cystitis Model.

In a bladder overactivity model of cystitis induced by intravesical infusion of acetic acid (a.a.), several parameters of spinal nerve stimulation (SNS) were optimized using continuous infusion cystometry. The optimal stimulation was further characterized through measurements of urodynamic function using single-fill cystometry. In anesthetized male rats, a cannula was placed into the bladder dome for saline or 0.3% a.a. infusion and intravesical pressure monitoring. For SNS, two teflon-coated stainless steel electrodes were placed bilaterally under each of the L6 spinal nerves, and current stimulation was controlled independently using two Grass stimulators. Stimulation of 1 Hz or 50 Hz at motor threshold (Tmot ) was ineffective for altering bladder activities, but 10-Hz SNS increased the infused volume (IV) in a stimulation intensity-dependent fashion (P < 0.01, mixed model repeated analysis). Pairwise comparisons of IV differences to each stimulation intensity show that IV during 1 × Tmot stimulation was significantly larger than 0 × Tmot (no stim, P = 0.001), while the IV during 2 × Tmot stimulation was significantly larger than other intensities tested (P < 0.01). The mean IV (±SEM) during 0 × Tmot (no stim), 0.5 × Tmot , 1 × Tmot , and 2 × Tmot were 0.23 ± 0.04 mL, 0.25 ± 0.03 mL, 0.26 ± 0.03 mL, and 0.40 ± 0.04 mL, respectively. In single-fill cystometry, 10-Hz SNS at 1 × Tmot and 2 × Tmot stimulation increased the IV, or voiding duration and threshold pressure. SNS did not produce significant effects on basal pressure and micturition pressure. SNS significantly attenuates hypersensitive micturition reflex; 10 Hz and high-intensity stimulation are mostly effective. Acute peripheral nerve activation increases the functional bladder capacity, which may be via mechanisms on the afferent arm of the bladder micturition reflex.

ADX71441, a novel, potent and selective positive allosteric modulator of the GABA(B) receptor, shows efficacy in rodent models of overactive bladder.

The GABAB receptor agonist baclofen reduces urethral resistance and detrusor overactivity in patients with spasticity. However, baclofen's side effects limit its use for the treatment of overactive bladder (OAB). Here, we tested a novel GABAB positive allosteric modulator (PAM) ADX71441 in models of OAB in mice and guinea pigs. Mice were left untreated or given (p.o.) vehicle (1% CMC), ADX71441 (1, 3, 10 mg kg(-1) ) or oxybutynin (100 mg kg(-1) ; Experiment 1) or vehicle (1% CMC), baclofen (1, 3, 6 mg kg(-1) ) or oxybutynin (Experiment 2). Treated mice were then overhydrated with water, challenged with furosemide, before being placed into micturition chambers and monitored for urinary parameters. In anaesthetized guinea pigs, intravesical infusion of acetic acid was used to induce OAB and the effects of ADX71441 (1, 3 mg kg(-1) ) or baclofen (1 mg kg(-1) ), administered i.v., on cystometric parameters were monitored. In mice, 10 mg kg(-1) ADX71441 increased urinary latencies, reduced the number of urinary events and the total and average urinary volumes. In guinea pigs, ADX71441 (1 and 3 mg kg(-1) ) increased the intercontraction interval (ICI) and bladder capacity (BC), and reduced micturition frequency (MF) compared to vehicle. At 3 mg kg(-1) ADX71441 completely inhibited the micturition reflex and induced overflow incontinence in five out of 10 animals. Baclofen slightly increased ICI and BC and reduced MF. Our findings demonstrate, for the first time, that a GABAB PAM has potential as a novel approach for the treatment of OAB.

Male lower urinary tract symptoms and α1D‐adrenoceptors

Historically, α(1)-adrenoceptors have been classified into three subtypes (α(1)(A), α(1)(B) and α(1)(D)) that are widely distributed in various organs. Research on the α(1)(D)-adrenoceptors in the bladder, urethra and prostate has focused on the relationship between expression levels and symptoms of bladder outlet obstruction, and the implications and functional roles of α(1)(D)-adrenoceptors subtypes in these organs. The α(1)(D)-adrenoceptor messenger ribonucleic acid and protein seem to be increased in obstructed bladders or small capacity bladders. In contrast, α(1)(D)-adrenoceptor subtype knock-out mice have been found to have a prolonged voiding interval. Interestingly, an α(1)(D)-adrenoceptor antagonist was found to inhibit the facilitation of afferent nerve activity for the micturition reflex induced by intravesical infusion of acetic acid. Clinically, patients who felt urgency at low filling volumes and had a small bladder capacity were found to have more α(1)(D)-adrenoceptor messenger ribonucleic acid in their bladder mucosa than patients who felt urgency at high filling volumes and had a large bladder capacity. An α(1)(D)-adrenoceptor antagonist was found to increase the first desired volume and the maximum desired volume while decreasing detrusor overactivity in pressure flow studies. Thus, α(1)(D)-adrenoceptors in the lower urinary tract might play an important role in the pathophysiology of lower urinary tract disorders.

Correlation between pharmacologically-induced changes in cystometric parameters and spinal c-Fos expression in rats

The inhibition of bladder sensory transmission is critical for the pharmacotherapy of urine storage symptoms. The purpose of this study is to examine the correlation between pharmacologically-induced changes in cystometric parameters and spinal c-Fos expression in anesthetized rats with bladder hyperactivity induced by the intravesical infusion of acetic acid. Animals were intravenously infused with either oxybutynin (OXY), a muscarinic receptor antagonist, tamsulosin (TAM), an α1-adrenoceptor antagonist, CL316243 (CL), a β3-adrenoceptor agonist, or saline. Morphine (MOR) treatment served as a positive control to inhibit bladder afferent activity. Intermicturition intervals, micturition pressure and pressure threshold were measured after intravesical acetic acid infusion. Animals were then perfused and spinal cords were removed. Sections from the L6 spinal cord were immunostained with an anti-c-Fos antibody, and c-Fos positive cells in the dorsal region were counted. CL and MOR significantly increased intermicturition intervals, whereas OXY and TAM had no significant effect on intermicturition intervals. While TAM and MOR did not affect the micturition pressure, OXY and CL caused a significant decrease. Pressure threshold was significantly decreased by CL and increased by MOR. All drugs significantly decreased the number of c-Fos positive cells with the following order of efficacy: MOR > CL > OXT > TAM. The number of c-Fos positive cells in each animal from all treatment groups was negatively correlated with its average intermicturition interval and pressure threshold, but not with its micturition pressure. Bladder afferent activity is suppressed by several clinically proven mechanisms as measured by c-Fos expression, despite the varied effects on cystometric parameters of each pharmacological treatment.

ATP released from the urothelium contributes to bladder hyperactivity induced by acetic acid in the rat

Event Abstract Back to Event ATP released from the urothelium contributes to bladder hyperactivity induced by acetic acid in the rat Jose E. Marinhas1*, D. Monteiro1, N. Silva1, M. Faria1, M. Duarte-Araujo1, M. Silva-Ramos1, 2 and P. Correia-de-Sa1 1 Instituto de Ciencias Biomedicas Abel Salazar - Universidade do Porto (ICBAS-UP), Laboratorio de Farmacologia e Neurobiologia, Unidade Multidisciplinar de Investigacao Biomedica (UMIB), Portugal 2 CHP - HGSA, Serv. Urologia, Portugal The bladder epithelium releases ATP in response to mechanical stimuli (and to chemical irritants), which may activate suburothelial sensory nerve fibers. Although the pathogenic mechanisms of bladder overactivity (OAB) are not fully understood, atropine-resistant purinergic reactivity increases in these patients (e.g. interstitial cystitis). Therefore, we aimed at investigating ATP release from the urothelium and the effects of this purine on bladder pressure and pelvic nerve activity in a in vivo rat model of hyperactive urinary bladder. Irritative cystometry (produced by the infusion of acetic acid, AA, 0.2-1% v/v) has been used to investigate new therapies from OAB.AA (0.2-1%, for 15 min) concentration-dependently decreased the time (ICI, 67 to 81% of control) and the pressure threshold (PTh, 58 to 85% of control) for appearance of the micturition reflex. Using the luciferin- luciferase luminescence assay (Enliten ATP kit, Promega, USA), we showed that urinary ATP increased (52±7%, n=5) following the micturition reflex. The concentration of urinary ATP was significantly (P<0.05) enhanced in the presence of AA (1%, 297±25%, n=3), while the activity of urinary lactate dehydrogenase (LDH) remained unchanged. Increases in the voiding frequency caused by AA (0.2%) were enhanced by intravesical infusion of the P2X1 and P2X3 agonist, alpha,beta-methyleneATP (30 μM), and of the ecto- ATPase inhibitor, ARL67156 (200 μM). PPADS, applied either by intravesical infusion (30 μM) or by intravenous bolus (17 μmol/Kg), reduced AA-induced bladder hyperactivity. However, in contrast to alpha,beta-methyleneATP (30 μM), PPADS also decreased the contraction amplitude. Blockade of ADP- sensitive P2Y1 receptors with MRS2179 (1 μmol/Kg, i.v.) increased the voiding frequency secondary to AA (0.2 %), but it was devoid of effect on the contraction amplitude.Although there is extensive literature indicating that many different types of purinoceptors are present in the lower urinary tract, the pathophysiological role of these receptors in OAB is still uncertain. Our results showed that ATP released from the urothelium play a role on bladder hyperactivity induced by intravesical infusion of acetic acid and that different subtypes of P2 purinoceptors regulate afferent nerve activity (P2X2/3 and P2Y1) and smooth muscle contractions (probably P2X2).Work supported by FCT, Soc. Port. Urologia and Univ. Porto / Caixa Geral de Depósitos. Conference: 11th Meeting of the Portuguese Society for Neuroscience, Braga, Portugal, 4 Jun - 6 Jun, 2009. Presentation Type: Poster Presentation Topic: Neuronal Communication Citation: Marinhas JE, Monteiro D, Silva N, Faria M, Duarte-Araujo M, Silva-Ramos M and Correia-de-Sa P (2009). ATP released from the urothelium contributes to bladder hyperactivity induced by acetic acid in the rat. Front. Neurosci. Conference Abstract: 11th Meeting of the Portuguese Society for Neuroscience. doi: 10.3389/conf.neuro.01.2009.11.148 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 12 Aug 2009; Published Online: 12 Aug 2009. * Correspondence: Jose E Marinhas, Instituto de Ciencias Biomedicas Abel Salazar - Universidade do Porto (ICBAS-UP), Laboratorio de Farmacologia e Neurobiologia, Unidade Multidisciplinar de Investigacao Biomedica (UMIB), Porto, Portugal, josemarinhas@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jose E Marinhas D. Monteiro N. Silva M. Faria M. Duarte-Araujo M. Silva-Ramos P. Correia-de-Sa Google Jose E Marinhas D. Monteiro N. Silva M. Faria M. Duarte-Araujo M. Silva-Ramos P. Correia-de-Sa Google Scholar Jose E Marinhas D. Monteiro N. Silva M. Faria M. Duarte-Araujo M. Silva-Ramos P. Correia-de-Sa PubMed Jose E Marinhas D. Monteiro N. Silva M. Faria M. Duarte-Araujo M. Silva-Ramos P. Correia-de-Sa Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A new method for producing urinary bladder hyperactivity using a non-invasive transient intravesical infusion of acetic acid in conscious rats

Introduction Animal models that closely resemble the pathophysiology of human overactive bladder are important for evaluating novel therapeutics to treat the disorder. We established a non-invasive hyperactive bladder model that is sensitive to anti-muscarinic drugs and without bladder inflammation. Methods Acetic acid solution was infused into the bladder for 5 min via the urethral orifice without any surgical procedures under isoflurane anaesthesia. After washing the bladder with saline, voiding frequency (VF) and total urine volume were determined for 9 h under conscious conditions. Results Infusion of a 0.5% acetic acid solution caused a significant increase in VF, without influencing total urine volume or inducing significant histopathological inflammatory alterations in the bladder urothelium. Oral administration of oxybutynin (3 and 10 mg/kg) significantly ameliorated increases in VF induced by 0.5% acetic acid. Infusion of 0.75% acetic acid induced intensive urinary inflammation and a decrease in total urine volume as well as an increase in VF. Oral treatment with oxybutynin (10 mg/kg) did not significantly improve the increased VF due to 0.75% acetic acid. Acetic acid (0.5%) infusion evoked bladder hyper-responsiveness whether applied at night or during the day. However, VF was increased more by the nighttime application of acetic acid, while there were no significant differences in basal levels of VF between daytime and nighttime. Discussion In this study, the non-invasive rat urinary hyperactive bladder model indicated minimizes the secondary effects of experimental procedures such as surgical operations and anesthesia on bladder function and is sensitive to oxybutynin. Thus, the model may be useful for investigating novel therapeutics for OAB treatment.

Activation of α 1D Adrenergic Receptors in the Rat Urothelium Facilitates the Micturition Reflex

Previous studies have revealed that the activation of alpha(1) adrenergic receptors in urothelial cells releases neurotransmitters. We determined if alpha(1D) adrenergic receptors are expressed in the urothelium of the rat bladder and if inhibition of these receptors affects reflex voiding. Female Wistar rats were used in the experiments. Receptor expression was evaluated by Western blot. The effects of receptor activation were studied using cystometrograms, measurement of adenosine triphosphate concentrations in the bladder lumen and afferent nerve recording. The alpha(1D) antagonist naftopidil (0.75 to 1.66 mg/kg) was administered intravenously into the external jugular vein. The expression of alpha(1D) adrenergic receptors was detected in urothelial tissue with Western blot and immunohistochemistry. The alpha(1D) receptor antagonist naftopidil prolonged the intercontraction interval during continuous infusion cystometrograms in conscious rats (143% of the control value) and suppressed the excitatory effect of intravesical infusion of acetic acid (0.1%) on the intercontraction interval (220%). Naftopidil inhibited the bladder afferent nerve activity induced by bladder distention (32.0%) and acetic acid infusion (30.4%), and decreased adenosine triphosphate levels in the bladder perfusate during bladder distention (36.6%). Endogenous catecholamines appear to act on alpha(1D) receptors in the urothelium to facilitate mechanosensitive bladder afferent nerve activity and reflex voiding.

The Involvement of the Tetrodotoxin-Resistant Sodium Channel Nav1.8 (PN3/SNS) in a Rat Model of Visceral Pain

The present study investigated the effect of inhibiting the expression of Na(v)1.8 (PN3/SNS) sodium channels by an antisense oligodeoxynucleotide (ODN) on bladder nociceptive responses induced by intravesical acetic acid infusion in rats. Animals were injected intrathecally with either Na(v)1.8 antisense or mismatch ODN. Control cystometrograms under urethane anesthesia during intravesical saline infusion exhibited intercontraction intervals (ICIs) that were significantly longer in antisense-treated rats than in mismatch ODN-treated rats. Intravesical infusion of 0.1% acetic acid induced bladder hyperactivity as reflected by a 68% reduction in ICIs in mismatch ODN-treated rats but did not significantly reduce ICIs in antisense-treated rats. The number of Fos-positive cells after acetic acid administration were significantly reduced in the L6 spinal cord from antisense-treated animals, compared with mismatch ODN-treated animals. In addition, Na(v)1.8 immunoreactivity was reduced in L6 dorsal root ganglion neurons in the antisense-treated rat. In patch-clamp recordings, the conductance density of TTX-resistant sodium currents in dissociated bladder afferent neurons that were labeled by axonal transport of a fluorescent dye, Fast Blue, injected into the bladder wall was also smaller in antisense-treated rats than in mismatch ODN-treated rats, whereas no changes were observed in TTX-sensitive currents. These results indicate that the Na(v)1.8 TTX-resistant sodium channels are involved in the activation of afferent nerves after chemical irritation of the bladder. These channels represent a new target for the treatment of inflammatory pain from visceral organs such as the urinary bladder.