Validation of Fenoterol to Study ß2-Adrenoceptor Function in the Rat Urinary Bladder.

Fenoterol is a ß2-adrenoceptor (AR)-selective agonist that is commonly used to investigate relaxation responses mediated by ß2-AR in smooth muscle preparations. Some data have questioned this because fenoterol had low potency in the rat urinary bladder when a muscarinic agonist was used as a pre-contraction agent and because some investigators proposed that fenoterol may act in part via ß3-AR. We designed the present study to investigate whether fenoterol is a proper pharmacological tool to study ß2-AR-mediated relaxation responses in the rat urinary bladder. Firstly, we have compared the effect of pre-contraction agents on fenoterol potency and found that fenoterol potency was about 1.5 log units greater against KCl than carbachol (pEC50 7.19 ± 0.66 and 5.62 ± 1.09 of KCl and of carbachol, respectively). To test the selectivity of fenoterol, we have determined the effects of the ß2-AR antagonist ICI 118,551 and the ß3-AR antagonist L 748,337 on relaxation responses to fenoterol. While 300 nM L 748,337 had little effect on the potency of fenoterol (pEC50 6.56 ± 0.25 and 6.33 ± 0.61 in the absence and presence of L 748,337, respectively), the relaxation curve for fenoterol was right-shifted in the presence 300 nM ICI 118,551 (pEC50 5.03 ± 0.18). Thus, we conclude that fenoterol is a proper pharmacological tool to assess ß2-AR-mediated responses in the rat urinary bladder and most likely in other smooth-muscle preparations containing multiple subtypes of the ß-AR.

Urinary Bladder Weight and Function in a Rat Model of Mild Hyperglycemia and Its Treatment With Dapagliflozin.

Hypertrophy and dysfunction of the urinary bladder are consistently observed in animal models of type 1 and less consistently in those of type 2 diabetes. We have tested the effects of mild hyperglycemia (n = 10 per group) in a randomized, blinded study and, in a blinded pilot study, of type 2 diabetes (n = 6 per group) and its treatment with dapagliflozin (1 mg/kg per day) on weight, contraction, and relaxation of the rat bladder. Based on a combination of high-fat diet and a low dose of streptozotocin, animals in the main study reached a mean peak blood glucose level of about 300 mg/dl, which declined to 205 mg/dl at study end. This was associated with a small, if any, increase in bladder weight. In a pooled analysis of all animals of the main and the pilot study, we detected a correlation of moderate strength between blood glucose and bladder weight (r 2 = 0.2013; P = 0.0003 for Pearson correlation coefficient). Neither the main nor the pilot study found evidence for an altered contractility (responses to carbachol or KCl) or relaxation (responses to isoprenaline, fenoterol, CL 316,243, or forskolin). Treatment with dapagliflozin in the absence of hyperglycemia increased diuresis in the main study by 43% relative to control and increased bladder weight by 15% in the pooled groups of both studies (post hoc analysis). We conclude that mild hyperglycemia has no major effects on bladder hypertrophy or function.

Protocol for a systematic review of guidelines for rigour in the design, conduct and analysis of biomedical experiments involving laboratory animals.

OBJECTIVE: Within the last years, there has been growing awareness of the negative repercussions of unstandardized planning, conduct and reporting of preclinical and biomedical research. Several initiatives have set the aim of increasing validity and reliability in reporting of studies and publications, and publishers have formed similar groups. Additionally, several groups of experts across the biomedical spectrum have published experience and opinion-based guidelines and guidance on potential standardized reporting. While all these guidelines cover reporting of experiments, an important step prior to this should be rigours planning and conduction of studies. The aim of this systematic review is to identify and harmonize existing experimental design, conduct and analysis guidelines relating to internal validity and reproducibility of preclinical animal research. The review will also identify literature describing risks of bias pertaining to the design, conduct and analysis of preclinical biomedical research. SEARCH STRATEGY: PubMed, Embase and Web of Science will be searched systematically to identify guidelines published in English language in peer-reviewed journals before January 2018 (box 1). All articles or systematic reviews in English language that describe or review guidelines on the internal validity and reproducibility of animal studies will be included. Google search for guidelines published on the websites of major funders and professional organisations can be found in (Box 2). SCREENING AND ANNOTATION: Unique references will be screened in two phases: screening for eligibility based on title and abstract, followed by screening for definitive inclusion based on full text. Screening will be performed in SyRF (http://syrf.org.uk). Each reference will be randomly presented to two independent reviewers. Disagreements between reviewers will be resolved by additional screening of the reference by a third, senior researcher. DATA MANAGEMENT AND REPORTING: All data, including extracted text and guidelines, will be stored in the SyRF platform. Elements of the included guidelines will be identified using a standardized extraction form. Reporting will follow the PRISMA guidelines as far as applicable.

Role of voiding and storage symptoms for the quality of life before and after treatment in men with voiding dysfunction.

PURPOSE: Previous studies on associations between voiding dysfunction and quality of life (QoL) have largely been limited to baseline data. Therefore, we have explored associations between Q (max) and voiding and storage sub-scores of the International Prostate Symptom Score (IPSS) before and after treatment with QoL. METHODS: Analysis of a single-center database of 2,316 men with voiding dysfunction attributed to benign prostatic hyperplasia undergoing various medical and surgical treatment forms. RESULTS: Q (max) exhibited little correlation with QoL before or after treatment. IPSS inversely correlated with QoL at baseline and after treatment, and IPSS improvements correlated with those of QoL. The associations applied to both the voiding and storage sub-score of the IPSS, with the latter consistently exhibiting somewhat tighter associations. CONCLUSIONS: Our post-treatment data support the idea of a cause-effect relationship between voiding symptoms and QoL irrespective of treatment form. While both voiding and storage symptoms contribute to this relationship, storage symptoms play a somewhat greater role.

Can [I]-Iodocyanopindolol Label ß(3)-Adrenoceptors in Rat Urinary Bladder?

ß(3)-Adrenoceptors have been demonstrated to mediate urinary bladder smooth muscle relaxation but proof of their expression at the protein level has been missing because of lack of suitable antibodies or radioligands. As among various available radioligands [(125)I]-iodocyanopindolol ([(125)I]-ICYP) exhibited the smallest problems in labeling cloned human ß(3)-adrenoceptors in previous studies, we have explored its suitability to label ß(3)-adrenoceptors in rat urinary bladder in saturation and competition radioligand binding experiments. Rat lung was used as an internal control and exhibited all characteristics expected from this tissue with regard to ß1/ß2-adrenoceptor labeling. Saturation and competition binding studies with [(125)I]-ICYP in rat bladder yielded saturable binding sites with an affinity compatible with ß(3)-adrenoceptors. In competition experiments various agonists and antagonists largely exhibited a profile compatible with a population consisting largely of ß(3)-adrenoceptors. However, the binding competition properties of ICI 118,551 and SR 59,230A were not easily explained by the idea of labeling a homogeneous ß(3)-adrenoceptor population but interpretation of the data was limited by a high degree of non-specific binding in [(125)I]-ICYP concentrations required to label the receptors. We conclude that [(125)I]-ICYP can be used to label tissue ß(3)-adrenoceptors but results obtained with this ligand have to be interpreted with caution.

Basic mechanisms of urgency: roles and benefits of pharmacotherapy.

INTRODUCTION: Since urgency is key to the overactive bladder syndrome, we have reviewed the mechanisms underlying how bladder filling and urgency are sensed, what causes urgency and how this relates to medical therapy. MATERIALS AND METHODS: Review of published literature. RESULTS: As urgency can only be assessed in cognitively intact humans, mechanistic studies of urgency often rely on proxy or surrogate parameters, such as detrusor overactivity, but these may not necessarily be reliable. There is an increasing evidence base to suggest that the sensation of 'urgency' differs from the normal physiological urge to void upon bladder filling. While the relative roles of alterations in afferent processes, central nervous processing, efferent mechanisms and in intrinsic bladder smooth muscle function remain unclear, and not necessarily mutually exclusive, several lines of evidence support an important role for the latter. CONCLUSIONS: A better understanding of urgency and its causes may help to develop more effective treatments for voiding dysfunction.

Effect of pre-contraction on ß-adrenoceptor-mediated relaxation of rat urinary bladder.

PURPOSE: The human physiological bladder contraction is largely mediated by acetylcholine acting on muscarinic receptors, but in pathophysiological settings the relative role of non-cholinergic stimuli gains importance. ß-Adrenoceptor agonists are currently in clinical development as treatments for the overactive bladder syndrome. Therefore, we have explored the ability of the ß-adrenoceptor agonist isoprenaline to induce rat isolated bladder strip relaxation on pre-contraction with the muscarinic agonist carbachol as compared to bladder tone induced by several non-cholinergic stimuli. METHODS: Bladder tone was induced by passive tension, receptor independently by KCl, carbachol, bradykinin or serotonin. Concentration­response curves were generated for relaxation by isoprenaline, and a single concentration of the receptor-independent relaxant forskolin was also tested. RESULTS: The various contractile stimuli induced different degrees of bladder tone, but the ability of isoprenaline or forskolin to relax rat bladder was not correlated with the degree of tone. Isoprenaline was significantly less potent and effective in causing relaxation against carbachol-induced tone than against any other stimulus, whereas no such relationship was observed for forskolin. CONCLUSIONS: We conclude that ß-adrenoceptor agonists can induce rat bladder relaxation against a wide range of contractile stimuli and are more potent and/or effective against non-cholinergic stimuli than against muscarinic agonism. This profile appears desirable for agents intended for the treatment of overactive bladder.