Differential Effects of Botulinum Neurotoxin A on Bladder Contractile Responses to Activation of Efferent Nerves, Smooth Muscles and Afferent Nerves in Rats

Takahashi, Ryuji; Yunoki, Takakazu; Naito, Seiji; Yoshimura, Naoki

doi:10.1016/j.juro.2012.07.001

Cited by 19 publications

(17 citation statements)

References 25 publications

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“…An early paper showed that BTXA inhibited release of ATP as well as ACh from parasympathetic nerves in the rat bladder [455] and confirmed subsequently [410,654]. More recent studies have shown that BTX also inhibited ATP release from urothelium ( [133,329,368,626]; and see [177]).…”

Section: Botulinum Toxin and Atp Releasementioning

confidence: 82%

Purinergic signalling in the urinary tract in health and disease

Burnstock

2013

Purinergic Signalling

140

149

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Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder t h e p u r i n e rg i c c o m p o n e n t o f p a r a s y m p a t h e t i c cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

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Section: Botulinum Toxin and Atp Releasementioning

confidence: 82%

Purinergic signalling in the urinary tract in health and disease

Burnstock

2013

Purinergic Signalling

140

149

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“…Our study completed the model of Smith et al and Takahashi et al [6,8] by controlling the viability of the bladder strips during the runs. We proved that the inhibitory effect of BoNT-A can be measured in vitro at low concentrations.…”

Section: Discussionmentioning

confidence: 96%

“…Howles et al on the other hand could not reproduce these measurements in another in vitro model [7]. Takahashi et al demonstrated inhibitory effect of BoNT-A in vitro however it was at a much higher concentration (>10 nM) than is used in clinical practice (10 U/1 mL onabotulinumtoxinA = 0.001 nM) [8]. In this study, we further developed and validated an in vitro model to measure the bioactivity of BoNT-A in lower concentrations.…”

Section: Introductionmentioning

confidence: 99%

Development of an in vitro model to measure bioactivity of botulinum neurotoxin A in rat bladder muscle strips

et al. 2014

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BackgroundBotulinum toxin A (BoNT-A) is a new treatment modality in various causes of bladder dysfunction; like neurogenic detrusor overactivity and overactive bladder. The best technique of administrating BoNT-A in patients is unknown. A validated in vitro model could be used to investigate newer intravesical administration techniques of BoNT-A. In this study, we describe the development and validation of in vitro model to measure inhibitory effects of BoNT-A on bladder strip contractions.MethodsRat bladder strips were mounted in organ baths filled with Krebs’ solution. The strips were stimulated chemically (80 mM potassium chloride, 1 μM carbachol) and electrically (Electrical Field Stimulation (EFS) 100 shocks, 50 V, 20 Hz, every 3 minutes). The viability of the strips was measured by carbachol stimulation at the beginning and at the end of the experiments. The strips were incubated in various concentrations of BoNT-A (0.03, 0.2, 0.3 nM). Controls were incubated in Krebs’ solution only. The inhibition of strip contraction induced by EFS was measured. These measurements were statistically analyzed with a log-logistic model representing diffusion.ResultsAll strips remained viable during the experiments. Inhibition of strip contraction was observed after incubation with 0.3 nM BoNT-A. The measurements fitted to a log-logistic model describing diffusion of BoNT-A in the bladder strip. The parameters of the log-logistic model representing diffusion were significant for 0.3 nM BoNT-A. Incubation with 0.2 nM BoNT-A showed insignificant results for 2 out of 3 runs. Incubation with 0.03 nM BoNT-A did not result in significant inhibition of strip contractions.ConclusionsAn in vitro model was developed and validated in which the inhibitory effect of low concentrations of BoNT-A on bladder strip contractions can be measured.

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“…In general drugs targeting membrane receptors have a relatively fast response (seconds to minutes), whereas drugs for intracellular targets ( e.g. , forskolin and other enzyme inhibitors 36 , botulinum toxin 37 ) require additional incubation time (30 min 3 hr). Additionally, tissue thickness may play a role.…”

Section: Discussionmentioning

confidence: 99%

Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology

Kullmann

Daugherty

Groat

et al. 2014

JoVE

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We describe an in vitro method to measure bladder smooth muscle contractility, and its use for investigating physiological and pharmacological properties of the smooth muscle as well as changes induced by pathology. This method provides critical information for understanding bladder function while overcoming major methodological difficulties encountered in in vivo experiments, such as surgical and pharmacological manipulations that affect stability and survival of the preparations, the use of human tissue, and/or the use of expensive chemicals. It also provides a way to investigate the properties of each bladder component (i.e. smooth muscle, mucosa, nerves) in healthy and pathological conditions. The urinary bladder is removed from an anesthetized animal, placed in Krebs solution and cut into strips. Strips are placed into a chamber filled with warm Krebs solution. One end is attached to an isometric tension transducer to measure contraction force, the other end is attached to a fixed rod. Tissue is stimulated by directly adding compounds to the bath or by electric field stimulation electrodes that activate nerves, similar to triggering bladder contractions in vivo. We demonstrate the use of this method to evaluate spontaneous smooth muscle contractility during development and after an experimental spinal cord injury, the nature of neurotransmission (transmitters and receptors involved), factors involved in modulation of smooth muscle activity, the role of individual bladder components, and species and organ differences in response to pharmacological agents. Additionally, it could be used for investigating intracellular pathways involved in contraction and/or relaxation of the smooth muscle, drug structure-activity relationships and evaluation of transmitter release. The in vitro smooth muscle contractility method has been used extensively for over 50 years, and has provided data that significantly contributed to our understanding of bladder function as well as to pharmaceutical development of compounds currently used clinically for bladder management.

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Differential Effects of Botulinum Neurotoxin A on Bladder Contractile Responses to Activation of Efferent Nerves, Smooth Muscles and Afferent Nerves in Rats

Cited by 19 publications

References 25 publications

Purinergic signalling in the urinary tract in health and disease

Purinergic signalling in the urinary tract in health and disease

Development of an in vitro model to measure bioactivity of botulinum neurotoxin A in rat bladder muscle strips

Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology

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