Tachykinins are expressed within bladder-innervating sensory afferents and have been shown to generate detrusor contraction and trigger micturition. The release of tachykinins from these sensory afferents may also activate tachykinin receptors on the urothelium or sensory afferents directly. Here, we investigated the direct and indirect influence of tachykinins on mechanosensation by recording sensory signaling from the bladder during distension, urothelial transmitter release ex vivo, and direct responses to neurokinin A (NKA) on isolated mouse urothelial cells and bladder-innervating DRG neurons. Bath application of NKA induced concentration-dependent increases in bladder-afferent firing and intravesical pressure that were attenuated by nifedipine and by the NK2 receptor antagonist GR159897 (100 nM). Intravesical NKA significantly decreased bladder compliance but had no direct effect on mechanosensitivity to bladder distension (30 µl/min). GR159897 alone enhanced bladder compliance but had no effect on mechanosensation. Intravesical NKA enhanced both the amplitude and frequency of bladder micromotions during distension, which induced significant transient increases in afferent firing, and were abolished by GR159897. NKA increased intracellular calcium levels in primary urothelial cells but not bladder-innervating DRG neurons. Urothelial ATP release during bladder distention was unchanged in the presence of NKA, whereas acetylcholine levels were reduced. NKA-mediated activation of urothelial cells and enhancement of bladder micromotions are novel mechanisms for NK2 receptor-mediated modulation of bladder mechanosensation. These results suggest that NKA influences bladder afferent activity indirectly via changes in detrusor contraction and urothelial mediator release. Direct actions on sensory nerves are unlikely to contribute to the effects of NKA.

The clinical use of cyclophosphamide and ifosfamide is limited by a resultant bladder toxicity which has been attributed to the metabolite acrolein. Another metabolite chloroacetaldehyde (CAA) associated with nephrotoxicity, has not been investigated for toxicity in the bladder and this study investigates the effects of acrolein and CAA on human urothelial cells in vitro. Human urothelial cells (RT4 and T24) were treated with acrolein or CAA and changes in cell viability, reactive oxygen species, caspase-3 activity and release of urothelial mediators ATP, acetylcholine, PGE2 were measured. The protective effects of N-acetyl cysteine (NAC) were also assessed. Both metabolites were toxic to human urothelial cells however, CAA significantly decreased cell viability at a 10-fold lower concentration (10µM) than acrolein (100µM). This was associated with increased ROS production and caspase-3 activity. NAC protected cells from these changes. In RT4 cells 100µM acrolein caused a significant increase in basal and stretch-induced ATP, Ach and PGE2 release. In T24 cells chloroacetaldehyde (10µM) increased basal and stimulated ATP and PGE2 levels. Again, NAC protected against changes in urothelial mediator release following acrolein or CAA. This study is the first to report that CAA in addition to acrolein contributes to the urotoxicity of cyclophosphamide and ifosfamide. Both metabolites altered urothelial mediator levels which could contribute to the sensory and functional bladder changes experienced by patients after treatment with cyclophosphamide or ifosfamide. Alterations in urothelial cell viability and mediator release may be causally linked to oxidative stress, with NAC providing protection against these changes.

It is well established that lower urinary tract symptoms (LUTS), particularly urinary urgency and incontinence, cause stress and anxiety for patients. However, there is mounting evidence that the relationship between these two factors is bidirectional and that chronic psychological stress itself can result in the development of symptoms such as urinary frequency, urgency, incontinence, and pelvic pain. This review considers the evidence that such a relationship exists and reviews the literature from clinical and animal studies to identify some of the mechanisms that might be involved. Inflammatory responses induced by chronic stress appear to offer the strongest link to bladder dysfunction. There is overwhelming evidence, both in patients and animal models, for a release of pro-inflammatory cytokines and chemokines during periods of chronic stress. Furthermore, cytokines have been shown to cause bladder dysfunction and pain via actions in the central nervous system and locally in the bladder. In the brain and spinal cord, pro-inflammatory cytokines influence the regulation of micturition pathways by corticotropin-releasing factor (CRF) and its receptors, while peripherally cytokines affect bladder function, directly causing detrusor hypertrophy and afferent nerve hypersensitivity. There is little information on which treatments may have most benefit for stressed/anxious patients with LUTS, but animal studies suggest traditional drugs for overactive bladder (solifenacin, mirabegron) are more effective on LUTS than anxiolytic drugs (fluoxetine, imipramine). The preliminary preclinical data for CRF receptor antagonists is not consistent. A clearer understanding of the mechanisms involved in stress-induced LUTS should provide a basis for improved treatment of this condition.

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The cytotoxic drugs cyclophosphamide (CPO) and ifosfamide (IFO) cause toxic urological effects due to the production of urinary metabolites that cause bladder inflammation. This study aimed to identify changes in the bladder afferent system following treatment with these drugs that might explain reported urological adverse effects.Intravesical pressure and afferent nerve activity were recorded during bladder distension and drug administration in isolated bladders from mice, 24 hours after intraperitoneal treatment with cyclophosphamide (100mg/Kg), ifosphamide (200mg/Kg) or saline (control).In isolated bladders, total afferent nerve activity at maximum bladder distension was increased from 182±13 imp/sec in control animals, to 230±14 imp/sec in CPO-treated (p<0.05) and 226±17 imp/sec in IFO-treated (P<0.001) mice. Single fibre analysis revealed the increase resulted from an enhanced activity in low threshold, wide dynamic range fibres (23.3±1.9 imp/sec/fibre in controls to 31.5±2.5 (p<0.01) in CPO and 29.9±2.0 imp/sec/fibre (p<0.05) in IFO treated). CPO treatment was accompanied by an increase in urinary frequency in vivo, but was not associated with increases in urothelial release of ATP or acetylcholine, bladder compliance or spontaneous muscle activity. Also,CPOtreatment did not affect afferent nerve responses or pressure responses to purinergic, muscarinic or nicotinic agonists. This is the first report of CPO and IFO-induced changes in specific populations of bladder afferents, namely an increase in low threshold, wide dynamic range fibres. These effects appear to be direct and not secondary to increases in smooth muscle activity or the release of urothelial mediators.

Psychological stress has been linked to the development and exacerbation of overactive bladder symptoms, as well as afferent sensitisation in other organ systems. Therefore, we aimed to investigate the effects of water avoidance stress on bladder afferent nerve activity in response to bladder filling and pharmaceutical stimulation with carbachol and ATP in mice. Adult female C57BL/6J mice were exposed to either water avoidance stress (WAS) for 1 h/day for 10 days or normal housing conditions. Voiding behaviour was measured before starting and 24-h after final stress exposure and then animals were euthanised to measure afferent nerve activity in association with bladder compliance, spontaneous phasic activity, contractile responses, as well as release of urothelial mediators. WAS caused increased urinary frequency without affecting urine production. The afferent nerve activity at low bladder pressures (4–7 mmHg), relevant to normal physiological filling, was significantly increased after stress. Both low and high threshold nerves demonstrated enhanced activity at physiological bladder pressures. Urothelial ATP and acetylcholine release and bladder compliance were unaffected by stress as was the detrusor response to ATP (1 mM) and carbachol (1 µM). WAS caused enhanced activity of individual afferent nerve fibres in response bladder distension. The enhanced activity was seen in both low and high threshold nerves suggesting that stressed animals may experience enhanced bladder filling sensations at lower bladder volumes as well as increased pain sensations, both potentially contributing to the increased urinary frequency seen after stress.

Background:Little is known about treatment provided to people living in nursing care facilities (NCFs) after hospital admission for hip fracture. In addition, there are no clinical guidelines for rehabilitation and recovery following hip fracture for nursing home residents.Methods: As part of a randomised trial (SACRED trial), which investigated the efficacy of a four week in-reach rehabilitation program, data were collected which described routine care for 240 people living in 76 nursing care facilities in South Australia who fractured their hips. The in-reach rehabilitation provided to 119 intervention participants is described, including intensity, type and methods used to encourage participation in rehabilitation. Adverse events that occurred, in particular falls, are also reported.Results: NCF records indicated that, over the four weeks following discharge from hospital after hip fracture, 76% of patients receiving usual care had a consultation with their general practitioner. Physiotherapy was provided to 79% of patients in usual care (median of 1.96 h over the 4 weeks, which is less than 30 min each week of physiotherapy). In-reach rehabilitation was provided by the hospital team for 13 h over the 4 weeks with almost full attendance at physiotherapy sessions (median of 1 missed session, range 0-7 with a median of 14 physiotherapy sessions attended by participants, range 1-18). Experienced therapists provided a flexible approach to the rehabilitation to account for patients' dementia and associated neuropsychiatric symptoms while providing dietetic support, mobility training and education to nursing home staff. The number of falls experienced by those in the intervention group was higher compared to those in usual care (Relative Risk 1.38 (95%CI 1.04-1.84, p = 0.03).Conclusions: Rehabilitation can be provided to people living in NCFs following hip fracture, even when they have moderate to severe dementia but the model needs to be flexible. Provision of rehabilitation may increase the rate of falls in this population. Further studies are required to establish the feasibility of the intervention in other long term care settings. (327 words). Trial registration: ACTRN12612000112864 registered on the Australian and New Zealand Clinical Trials Registry (ANZCTR).

Background and purpose: The internal anal sphincter has been shown to contract in response to a 1 -adrenoceptor stimulation and therefore a 1 -adrenoceptor agonists may be useful in treating faecal incontinence. This study characterizes the a 1 -adrenoceptor subtype responsible for mediating contraction of the internal anal sphincter of the pig. Experimental approach: The potency of agonists and the affinities of several receptor subtype selective antagonists were determined on smooth muscle strips for the pig internal anal sphincter. Cumulative concentration-response curves were performed using phenylephrine and noradrenaline. Key results: The potency of the a 1A -adrenoceptor selective agonist A61603 (pEC 50 ¼ 7.79±0.04) was 158-fold greater than that for noradrenaline (pEC 50 ¼ 5.59 ± 0.02). Phenylephrine (pEC 50 ¼ 5.99 ± 0.05) was 2.5-fold more potent than noradrenaline. The a 1D -adrenoceptor selective antagonist BMY7378 caused rightward shifts of the concentration-response curves to phenylephrine and noradrenaline, yielding low affinity estimates of 6.59 ± 0.15 and 6.33 ± 0.13, respectively. Relatively high affinity estimates were obtained for the a 1A -adrenoceptor selective antagonists, RS100329 (9.01±0.14 and 9.06±0.22 with phenylephrine and noradrenaline, respectively) and 5-methylurapidil (8.51 ± 0.10 and 8.31 ± 0.10, respectively). Prazosin antagonized responses of the sphincter to phenylephrine and noradrenaline, yielding mean affinity estimates of 8.58±0.10 and 8.15 ± 0.08, respectively. The Schild slope for prazosin with phenylephrine was equal to unity (1.01 ± 0.24), however the Schild slope using noradrenaline was significantly less than unity (0.50±0.11, Po0.05). Conclusion and implications:The results suggest that contraction of circular smooth muscle from the pig internal anal sphincter is mediated via a population of adrenoceptors with the pharmacological characteristics of the a 1A/L -adrenoceptor, most probably the a 1L -adrenoceptor form of this receptor.