Effect of clenbuterol on contractile response in periurethral striated muscle of rabbits

Clinical Guideline for Female Lower Urinary Tract Symptoms

The "Japanese Clinical Guideline for Female Lower Urinary Tract Symptoms," published in Japan in November 2013, contains two algorithms (a primary and a specialized treatment algorithm) that are novel worldwide as they cover female lower urinary tract symptoms other than urinary incontinence. For primary treatment, necessary types of evaluation include querying the patient regarding symptoms and medical history, examining physical findings, and performing urinalysis. The types of evaluations that should be performed for select cases include evaluation with symptom/quality of life (QOL) questionnaires, urination records, residual urine measurement, urine cytology, urine culture, serum creatinine measurement, and ultrasonography. If the main symptoms are voiding/post-voiding, specialized treatment should be considered because multiple conditions may be involved. When storage difficulties are the main symptoms, the patient should be assessed using the primary algorithm. When conditions such as overactive bladder or stress incontinence are diagnosed and treatment is administered, but sufficient improvement is not achieved, the specialized algorithm should be considered. In case of specialized treatment, physiological re-evaluation, urinary tract/pelvic imaging evaluation, and urodynamic testing are conducted for conditions such as refractory overactive bladder and stress incontinence. There are two causes of voiding/post-voiding symptoms: lower urinary tract obstruction and detrusor underactivity. Lower urinary tract obstruction caused by pelvic organ prolapse may be improved by surgery.

beta(2)-adrenergic agonists and pelvic floor exercises for female stress incontinence

OBJECTIVE

We compared beta(2)-adrenergic agonist therapy with clenbuterol (DT) and physiological therapy (PT) in a randomized study to establish the first line therapy for stress incontinence (SI).

METHOD

The clinical efficacy of DT (group A), PT (group B), and a combination of DT and PT (group C) was investigated in 61 patients with SI by means of a 12-week randomized controlled study. The frequency and volume of SI and the patients' own impressions were used as the basis for the assessment of efficacy.

RESULTS

The SI improvement rates in groups A, B, and C were 76.9, 52.6, and 89. 5%, respectively (P=0.0361). A significant therapeutic effect on the frequency of SI was observed in group B and group C at 2 weeks after the start of treatment (both P<0.05), and in all groups at 6 weeks (all P<0.01). The efficacy rates based on the patients' own impressions in groups A, B, and C were 84.6, 31.6, and 68.4%, respectively (P=0.0064).

CONCLUSION

The beta(2)-adrenergic agonist appeared to be clinically useful as a drug of choice for SI.

Function and distribution of beta3-adrenoceptors in rat, rabbit and human urinary bladder and external urethral sphincter

1. Activation of beta-adrenoceptors causes relaxation of the urinary bladder and contraction of the external urethral sphincter, which consists of fast-contracting skeletal muscles. A beta2-adrenoceptor agonist, clenbuterol, recently has been developed as a therapeutic drug for the treatment of urinary incontinence, however beta2-adrenoceptor agonists have undesirable effects on cardiac and striated muscle function. 2. In this study, we compared the effects of the beta2-adrenoceptor agonist, clenbuterol and of a novel beta3-adrenoceptor agonist, GS332, on urinary bladder and external urethral sphincter function in rat, rabbit and human. We also determined the distribution of beta3-adrenoceptors in human urinary bladder and external urethral sphincter, using radioligand-binding techniques. 3. Clenbuterol induced marked relaxations in rat, rabbit and human urinary bladder smooth muscles and also induced marked contractions in rat periurethral striated muscles (external urethral sphincter), while GS332 induced marked relaxations in rat and human, but not in rabbit, urinary bladder smooth muscles and induced small contractions in rat periurethral striated muscles. 4. The radioligand binding studies showed presence of beta2- and beta3-adrenoceptors in human urinary bladder, external urethral sphincter and abdominal rectus muscles. The affinities of GS332 were the highest in urinary bladder and the lowest in the skeletal (abdominal rectus) muscles, while the affinities of clenbuterol were similar in urinary bladder, external urethral sphincter and the skeletal (abdominal rectus) muscles. 5. These results suggest that GS332 could, similarly clenbuterol, have a role in the treatment of urinary frequency and urinary incontinence.