Effects of some antidepressants on the volume-induced reflex contractions of the rat urinary bladder: lack of correlation with muscarinic receptors affinity

The inhibitory effect of escitalopram on mouse detrusor contractility: The role of L-type calcium channels

Selective serotonin reuptake inhibitors (SSRIs) are associated with urinary problems attributed to their central effects. ESC is a preferred SSRI and several case reports described that ESC is related to urinary retention. However, the direct effect of ESC on detrusor contractility is still not completely elucidated. Thus, we investigated the effect of ESC on detrusor contractility and mechanism(s) of its action in isolated mouse detrusor strips. Molecular docking and measurement of intracellular calcium were performed to determine the possible calcium channel blocking effect of ESC. The contractile responses to carbachol (CCh), KCl and electrical field stimulation of detrusor strips were significantly abolished by ESC (10 or 100 μM). ESC relaxed KCl-precontracted detrusor strips concentration-dependently, which was not affected by tetraethylammonium, glibenclamide, 4-aminopyridine, propranolol, L-NAME or methylene blue. ESC (10 or 100 μM) reduced both the CaCl₂- and CCh-induced contractions under calcium-free conditions, indicating the role of calcium-involved mechanisms in ESC-mediated relaxation. Furthermore, ESC significantly decreased Bay K8644-induced contraction and the cytosolic calcium level in fura-2-loaded A7r5 cells. Molecular docking study also revealed the potential of ESC to bind L-type calcium (Ca_v1) channels. Our results demonstrate that ESC inhibits detrusor contractility via blocking Ca_v1 channels, which provides evidence for the direct effect of ESC on detrusor contractility and its mechanism.

Emerging drugs for treatment of overactive bladder and detrusor overactivity

BACKGROUND

Overactive bladder (OAB) signifies the presence of urinary urgency and can have major effects on quality of life and social functioning. Standard antimuscarinic drugs have good initial response rates but substantial adverse effects and long-term compliance problems.

OBJECTIVES

To review the complexities of the mechanisms underlying OAB and the current drugs available for treating its symptoms.

METHODS

The literature was reviewed to define current therapies and drugs in clinical trials. Articles were identified by means of a computerised PubMed and Cochrane Library search (using the following keywords: overactive bladder, detrusor overactivity, urgency and bladder), supported by a search of the PharmaProjects database.

CONCLUSIONS

New drug classes, such as beta-3 adrenergic agonists, may work by reducing contractility or excitability of bladder muscle. Moderation of afferent activity may allow improved OAB symptoms, with lower risk of affecting voiding function. Agents acting on the CNS could influence OAB favourably, but target selection and adverse effects are an issue. The recognition of the functional contribution of the urothelium and the diversity of nerve transmitters has sparked interest in both peripheral and central modulation of OAB pathophysiology.

Low dose citalopram reverses memory impairment and electroconvulsive shock-induced immobilization

Citalopram, a selective serotonin reuptake inhibitor (SSRI), is one of the most widely used antidepressants. Recently, citalopram has been reported to improve working memory in patients with depression, and psychotic symptoms and behavioral disturbances in patients with dementia. However, the possibility of using citalopram in the treatment of cognitive disorders has not received much attention. The present study investigated the effects of citalopram on scopolamine- and Delta9-tetrahydrocannabinol (THC)-induced impairment of spatial memory using an eight-arm radial maze and electroconvulsive shock (ECS)-induced immobilization (a behavioral model for the disturbance of consciousness). Low dose citalopram reversed both scopolamine- and THC-induced impairment of spatial memory, suppressed ECS-induced immobilization reversed the THC-induced decrease of acetylcholine (ACh) release in the dorsal hippocampus in vivo microdialysis, and enhanced tremors induced by oxotremorine, a muscarinic M1 receptor agonist. Taken together these findings suggest that low dose citalopram is useful for the treatment of memory deficits and consciousness disturbance.

Fluvoxamine is ineffective in the treatment of enuresis in children and adolescents: an open-label pilot study

Tricyclic antidepressants possess established antienuretic properties. The selective serotonin reuptake inhibitors (SSRIs) have similar antidepressant properties to the tricyclic antidepressants and a safer side effect profile. The aim of the present study was to evaluate the antienuretic efficacy of one SSRI, fluvoxamine. Nine children aged 9 to 14 years with primary enuresis which was resistant to behavioral therapy participated in the study. All received fluvoxamine, 75-100 mg per day. In four, the enuresis was the only focus of clinical attention, and five received fluvoxamine for other primary indications. Enuresis was monitored daily, and mean voiding frequency was compared between three phases: baseline, on treatment and off treatment. Fluvoxamine had no statistically significant effect on enuresis. Fluvoxamine does not seem to possess significant antienuretic properties. We suggest that the combination of serotonergic with anticholinergic activity is a major factor in the antienuretic activity. In the treatment of children or adolescents with obsessive-compulsive disorder and comorbid enuresis, clomipramine may be preferred over SSRIs. Copyright 2001 John Wiley & Sons, Ltd.

Urinary bladder function and drug development

Disorders of the bladder are extremely common and are becoming more so in an ageing population. Recently, our understanding of lower urinary tract physiology and pathology has also increased. Here, Douglas Ferguson and Nim Christopher summarize this new knowledge of lower urinary tract function, the changes in innervation that occur with age and the common disease states, and discuss how it is being used to develop new drug treatments for bladder disorders.