The effect of terazosin on bladder function in the spinal cord injured patient

Urodynamic findings and therapeutic approaches for neurogenic lower urinary tract dysfunction in patients with thoracic spinal cord injury

OBJECTIVES

To evaluate urodynamic examination results and treatment methods of neurogenic lower urinary tract dysfunction (NLUTD) in patients with traumatic thoracic spinal cord injury (SCI).

METHODS

Ninety-one patients with traumatic thoracic SCI were included in the study. The urodynamic analyses of the patients were conducted retrospectively using their laboratory outcomes. The patients were divided into subgroups according to the sensory innervation of the bladder (T1-10/T11-12), the preservation of sensory functions in the sacral segment (complete lesion/incomplete lesion), and the duration of injury (< 6 months/ ≥ 6 months) and evaluations in subgroups were carried out.

RESULTS

A total of 91 patients (69 males, 22 females) were included in the study. When comparing between the subgroups, the sense of bladder fullness was preserved more in the T11-T12 group with a statistically significant difference (p < 0.001). While storage disorder, the rate of indwelling catheter use during hospitalization, bacterial growth of 105 CFU/ml in the urine culture, and anticholinergic drug recommendation after urodynamic examination were higher in the complete lesion group, the rate of spontaneous/catheter-free voiding, the number of patients in which sense of bladder fullness was preserved-partially preserved, and alpha-blocker drug recommendation after urodynamic examination was higher in the incomplete lesion group, with a statistically significant difference in all parameters (all p values < 0.05).

CONCLUSION

Our results demonstrate that there are differences in neurogenic lower urinary tract dysfunction features in subgroups of traumatic thoracic SCI patients. Regular urinary system evaluation and necessary changes in treatment should be carried out in this patient group.

Conservative Bladder Management and Medical Treatment in Chronic Spinal Cord Injury Patients

To review the available data on non-surgical management for neurogenic lower urinary tract dysfunction (NLUTD) in patients with chronic spinal cord injury (SCI) and provide the most updated knowledge for readers. We categorized the bladder management approaches into storage and voiding dysfunction separately; both are minimally invasive, safe, and efficacious procedures. The main goals for NLUTD management are to achieve urinary continence; improve quality of life; prevent urinary tract infections and, last but not least, preserve upper urinary tract function. Annual renal sonography workups and regular video urodynamics examinations are crucial for early detection and further urological management. Despite the extensive data on NLUTD, there are still relatively few novel publications and there is a lack of high-quality evidence. There is a paucity of new minimally invasive and prolonged efficacy treatments for NLUTD, and a partnership between urologists, nephrologists and physiatrists is required to promote and ensure the health of SCI patients in the future.

Real world treatment patterns in the neurogenic bladder population: a systematic literature review

Myriad treatment modalities are available for neurogenic bladder (NGB) including behavioral therapies, oral pharmacotherapy, catheterization and surgical procedures. Little is known about how NGB patients are managed in the real world, how well patterns relate to clinical guidelines and how strategies may have changed over time. To address this gap, a systematic review (SR) was conducted using MEDLINE and EMBASE [1996–2017]. The inclusion criteria for studies were: (I) published in English; (II) conducted in human subjects; (III) reporting the treatment patterns/use in NGB; (IV) conducted in a real world setting. A narrative synthesis of results was conducted, comparing the results to current treatment guidelines. Percentage of treatment use was summarized using ranges. Eight studies met the inclusion criteria. Although most studies focused on spinal cord injuries (SCI), study designs and settings were heterogeneous. All data was collected before 2007. The most popular form of oral pharmacotherapy was antimuscarinics, used by 12.6–86.7% of patients; 0–100% of patients used catheterization techniques, 2.5–53.1% used reflex voiding (RV), and 0.2–55% underwent surgery. A notable amount of patients switched treatments. This SR revealed that numerous strategies have been used to manage NGB throughout the years and there has been a large variance in their use. Whilst there were some discrepancies, most practices matched recommendations made in current guidelines. Ultimately, this SR showed that there is a large gap of epidemiological studies conducted in the field of NGB and the authors felt that available data was insufficient to build a comprehensive picture of treatment patterns. Epidemiological studies using electronic medical records (EMRs) are necessary to advance our understanding of how treatment patterns have changed, and also build a comprehensive picture of how patients are managed in current practice.

Intracerebral haemorrhage following uncontrolled autonomic dysreflexia post suprapubic catheter placement surgery

INTRODUCTION

We describe a case of intracerebral haemorrhage (ICH) following uncontrolled episodes of autonomic dysreflexia (AD) within 24 h of a minor urological procedure.

CASE PRESENTATION

A 33-year-old active paraplegic patient T1 Association Impairment Scale A underwent an elective suprapubic catheter (SPC) placement for bladder management. The surgery was done under general anaesthesia and was uneventful. Four hours after surgery, he developed haematuria and multiple blood clots in the urine, which eventually caused blockage of the SPC and resulted in symptomatic AD. The clots and blockage persisted, which continued to trigger repeated episodes of increased blood pressure (BP) and AD. Despite medical treatment with sublingual nitrate to lower the increased BP, the patient subsequently developed massive left ICH presenting with right upper limb weakness, facial asymmetry and inability to speak. He continued to have fluctuating BP measurements for 11 days post event with severe hypertensive and hypotensive episodes. This presented a challenge in the BP management as well as post-ICH management. He underwent an intensive neurorehabilitation programme as soon as the BP had stabilized.

DISCUSSION

Severe neurological complications of AD are rare. In this case report, we highlight the importance of close monitoring of BP and AD symptoms after an SPC procedure, the challenges in BP management and the subsequent importance of an early rehabilitation programme after ICH secondary to uncontrolled AD.

Changes in sympathetic neurovascular function following spinal cord injury

The effects of spinal cord injury (SCI) on sympathetic neurovascular transmission have generally been ignored. This review describes changes in sympathetic nerve-mediated activation of arterial vessels to which ongoing sympathetic activity has been reduced or silenced following spinal cord transection in rats. In all vessels studied in rats, SCI markedly enhanced their contractile responses to nerve activity. However, the mechanisms that augment neurovascular transmission differ between the rat tail artery and mesenteric artery. In tail artery, the enhancement of neurovascular transmission cannot be attributed to changes in sensitivity of the vascular muscle to α₁- or α₂-adrenoceptor agonists. Instead the contribution of L-type Ca²⁺ channels to activation of the smooth muscle by nerve-released noradrenaline is greatly increased following SCI. By contrast, mesenteric arteries from SCI rats had increased sensitivity to phenylephrine but not to methoxamine. While both phenylephrine and methoxamine are α₁-adrenoceptor agonists, only phenylephrine is a substrate for the neuronal noradrenaline transporter. Therefore the selective increase in sensitivity to phenylephrine suggests that the activity of the neuronal noradrenaline transporter is reduced. While present evidence suggests that sympathetic vasoconstrictor neurons do not contribute to the normal regulation of peripheral resistance below a complete SCI in humans, the available evidence does indicate that these experimental findings in animals are likely to apply after SCI in humans and contribute to autonomic dysreflexia.

α1D-Adrenoceptor blockade increases voiding efficiency by improving external urethral sphincter activity in rats with spinal cord injury

Ideal therapy for lower urinary tract dysfunction in patients with spinal cord injury (SCI) should decrease detrusor overactivity, thereby promoting urine storage at low intravesical pressure and promoting efficient voiding at low pressure by decreasing detrusor-sphincter dyssynergia. Here we investigated blockade of various α-adrenoceptors to determine the subtype that was principally responsible for improving the voiding dysfunction. The effects of the intravenous α-blocker naftopidil, the α-blocker BMY 7378, and the α-blocker silodosin were evaluated using cystometrography and external urethral sphincter-electromyography (EMG) in decerebrated, unanesthetized female Sprague-Dawley rats with chronic SCI following transection at Th8. Parameters measured included the voided volume, residual volume, voiding efficiency, and burst and silent periods on EMG. Compared with values in decerebrated non-SCI rats, EMG of decerebrated SCI rats revealed more prominent tonic activity, significantly shorter periods of bursting activity, and a reduced ratio of the silent to active period during bursting. Compared with the value before drug administration (control), the voiding efficiency was significantly increased by naftopidil (1 and 3 mg/kg) (<0.05 each), and the burst (<0.01 and <0.05, respectively) and silent periods (<0.01 each) on EMG were significantly lengthened. BMY 7378 (1 mg/kg) significantly increased voiding efficiency and lengthened the burst periods (<0.05 each). Silodosin did not affect any parameters. These results suggest that α-blockade reduces the urethral resistance associated with detrusor-sphincter dyssynergia, thus improving voiding efficiency in SCI rats.

Medical management of neurogenic bladder with oral therapy

This is a review of the most current literature on medical management of the neurogenic bladder (NGB) to treat detrusor overactivity (DO), improve bladder compliance and treat urinary incontinence. The use of antimuscarinics, alpha blockers, tricyclic antidepressants, desmopressin and mirabegron will be discussed along with combination therapy to improve efficacy. These medical therapies will be the focus of this review with surgical therapy and botulinum toxin injections being the subject of other articles in this series.

Effects of bladder function by early tamsulosin treatment in a spinal cord injury rat model

Objective

To investigate the effects of early tamsulosin treatment on changes in bladder characteristics after a spinal cord injury.

Methods

We divided 45 rats into three groups: the control (CON) group, the spinal cord injury (SCI) group, and the SCI+tamsulosin treatment (SCI+TAM) group. Spinal cord transection was performed in the SCI and SCI+TAM groups. Tamsulosin was injected for 7 days in the SCI+TAM group. Intravesical and intra-abdominal catheters were implanted before cord injury. Basal pressure (BP), maximal vesical pressure (MVP), micturition volume (MV), and voiding interval time (VIT) were measured at 7 days after SCI. The bladder was then removed and used for an in vitro organ bath study and Western blot analysis. The percentage changes in contractility from baseline after acetylcholine alone, pretreatment with a muscarinic 2 (M2) receptor blocker (AQ-RA741), and pretreatment with a M3 receptor blocker (4-DAMP) were compared among the groups. Western blot analyses were performed to determine expression levels of pERK1/2 and rho-kinase.

Results

In cystometry, MVP, BP, MV, and VIT showed changes in the SCI and SCI+TAM groups versus the CON group (p<0.05). In the organ bath study, acetylcholine-induced contractility in the three groups differed significantly (p<0.05). Additionally, acetylcholine-induced contractility with 4-DAMP pretreatment was reduced significantly in the SCI+TAM group versus the SCI group. In Western blotting, pERK1/2 expression was stronger (p<0.05) and rho-kinase expression was weaker in the SCI+TAM group than the SCI group (p<0.05).

Conclusion

These results suggest that the bladder contraction due to acetylcholine after SCI can be decreased by tamsulosin in the acute stage and this involves changes in pERK1/2 and rho-kinase.

Sexual function and autonomic dysreflexia in men with spinal cord injuries: how should we treat?

STUDY DESIGN

Systematic review.

OBJECTIVES

Review the literature on the acute or prophylactic treatment of autonomic dysreflexia in the context of sexual activities.

SETTING

International.

METHODS

Medline search using AD and spinal cord injury and all years of publication.

RESULTS

Thirty-seven papers on the specific treatment of AD showed that nifedipine, prazosin, captopril and clonidine are candidates in the context of sexual activities. Prazosin, however, has an initial hypotensive effect requiring to begin treatment 12 h before intercourse, which makes it less ideal for spontaneous sexual activities. Captopril has an initial hypotensive effect and was only studied in acute AD. Its usefulness in prophylaxis remains to be demonstrated. Clonidine has successfully been used clinically for decades, but never studied in randomized control trials. Nifedipine remains the most widely studied and significant treatment of AD whether in acute or prophylactic conditions. Recent concerns suggest increased cardiovascular risks with sublingual nifedipine in non-SCI populations, but negative long-term effects have not been reported in the SCI population.

CONCLUSION

Sexual function is a priority for men with SCI. As sexual activities, in particular ejaculation, can be a source of AD, adequate treatments and prophylaxis must be considered in the context of sexual activities. Experts must meet and conclude on the thresholds, parameters and treatments that should be considered in the long-term management of AD in the context of sexual function in men with SCI.

Predictive factors for the effect of the α1-D/A adrenoceptor antagonist naftopidil on subjective and objective criteria in patients with neurogenic lower urinary tract dysfunction

OBJECTIVES

• To assess the effect of α1-D/A adrenoceptor antagonist naftopidil on patients with neurogenic lower urinary tract dysfunction (NLUTD) and voiding difficulty. • To explore the effectiveness of naftopidil in these patients by using urodynamic variables, including pressure flow study (PFS), and to find good and simple parameters (International Prostate Symptom Score (IPSS), Post-void residual urine (PVR), and uroflowmetry (UFM) parameters) as substitution of PFS for predicting the effect of naftopidil.

PATIENTS AND METHODS

• The main inclusion and exclusion criteria were, IPSS ≥8, voiding symptoms with IPSS ≥5, IPSS-quality of life (QOL) ≥2, PVR ≥50 mL, and without prostatic enlargement ≥ 20 mL. • After initial assessment, patients were stepwisely administered for 12 weeks with the following: placebo for 2 weeks, naftopidil 25 mg/day for 2 weeks, naftopidil 50 mg/day for 2 weeks, and naftopidil 75 mg/day for 6 weeks. At the end of both placebo and 6 weeks' naftopidil 75 mg/day, their IPSS, UFM, PVR, and PFS were assessed. • A total of 82 Japanese patients (men 40, women 42) with lower urinary tract symptoms complicated by NLUTD, with a mean age of 63.9 years, were included from private or institutional clinics. • The lesions were spinal cord 42, and peripheral nervous system 40. The spinal cord lesions were all lumbar spine (injury or lumbar canal stenosis).

RESULTS

• In all patients, pressure at maximum urinary flow rate (P(det) Q(max) ) in PFS significantly decreased (P < 0.05), and maximum urinary flow rate in UFM significantly increased (P < 0.01). Analysis of data for men and for women also showed a significant decrease in PVR, %PVR, and total IPSS score. • The degree of improvement of voided volume, PVR (%), and IPSS in patients with PVR <300 mL was significantly greater than those in patients with PVR ≥300 mL. • The degree of improvement of P(det) Q(max) in PFS, and IPSS in patients with bladder contractility was significantly greater than that in patients without bladder contractility.

CONCLUSIONS

• α1-D/A adrenoceptor antagonist naftopidil has a significant effect on both symptoms and urodynamic variables of patients of both genders with NLUTD in Japan. • PVR <300 mL and bladder contractility are predictive factors for the efficacy of naftopidil on patients with NLUTD.

A systematic review of the management of autonomic dysreflexia after spinal cord injury

OBJECTIVE

To review systematically the clinical evidence on strategies to prevent and manage autonomic dysreflexia (AD).

DATA SOURCES

A key word search of several databases (Medline, CINAHL, EMBASE, and PsycINFO), in addition to manual searches of retrieved articles, was undertaken to identify all English-language literature evaluating the efficacy of interventions for AD.

STUDY SELECTION

Studies selected for review included randomized controlled trials (RCTs), prospective cohort studies, and cross-sectional studies. Treatments reviewed included pharmacologic and nonpharmacologic interventions for the management of AD in subjects with spinal cord injury. Studies that failed to assess AD outcomes (eg, blood pressure) or symptoms (eg, headaches, sweating) were excluded.

DATA EXTRACTION

Studies were critically reviewed and assessed for their methodologic quality by 2 independent reviewers.

DATA SYNTHESIS

Thirty-one studies were assessed, including 6 RCTs. Preventative strategies to reduce the episodes of AD caused by common triggers (eg, urogenital system, surgery) primarily were supported by level 4 (pre-post studies) and level 5 (observational studies) evidence. The initial acute nonpharmacologic management of an episode of AD (ie, positioning the patient upright, loosening tight clothing, eliminating any precipitating stimulus) is supported by clinical consensus and physiologic data (level 5 evidence). The use of antihypertensive drugs in the presence of sustained elevated blood pressure is supported by level 1 (prazosin) and level 2 evidence (nifedipine and prostaglandin E(2)).

CONCLUSIONS

A variety of options are available to prevent AD (eg, surgical, pharmacologic) and manage the acute episode (elimination of triggers, pharmacologic); however, these options are predominantly supported by evidence from noncontrolled trials, and more rigorous trials are required.

[Disorders of bladder compliance and neurogenic bladder]

Bladder compliance is defined as the relationship between change in bladder volume and change in detrusor pressure (DV/DP). The pathophysiology of neurogenic disorders of bladder compliance is still poorly understood. Experimental reduction of blood flow in the bladder wall, bilateral hypogastric nerve section in rats, the study of spinalized rat bladders, and reduction of oestrogen impregnation show that these conditions induce loss of the viscoelastic properties of the bladder. With the arrival of new treatments active on afferent and/or efferent pathways or on the central nervous system, it is very important to improve our understanding of the pathophysiology of neurogenic disorders of bladder compliance. The reversibility of these disorders constitutes a major therapeutic challenge and their functional consequences constitute a crucial prognostic element of neurogenic bladder. Disorders of bladder compliance can be assessed clinically from two points of view: 1) The natural history of onset of these disorders in neurogenic bladder. Clinical experience demonstrates certain risk factors for the development of these disorders, such as the voiding mode (intermittent self-catheterization or by a carer versus indwelling catheter), the level of the spinal cord lesion (suprasacral versus sacral, incomplete versus complete, and cauda equina lesions), and the presence of myelomeningocele. 2) Data derived from conservative management of these disorders in patients with neurogenic bladder: urethral dilatation, various types of sphincterotomy, vesical denervation, alpha-blockers, sympatholytics, vanilloids (resiniferatoxin and capsaicin), intra-detrusor botulinum toxin and intrathecal baclofen have been shown to improve disorders of compliance of neurogenic bladder.

Alpha1 Adrenoceptors in Human Urinary Tract: Expression, Distribution and Clinical Implications

Adrenergic receptors (ARs) are a class of proteins belonging to the G protein-coupled receptor family. Pharmacological and molecular studies allowed dividing ARs into three different categories: α1, α2 and β. In this review, we focused on α1 ARs and α1 AR antagonists, since α 1 ARs play an important role in the pathophysiology of a number of urinary tract (UT) dysfunctions. α1 ARs are widely expressed in human UT; in particular, the three ureter areas (distal, medial and proximal) show different patterns of receptor expression (i.e. distal > medial = proximal), giving the molecular basis for the use of α1 ARs antagonist in the expulsive therapy of distal ureter calculi. Bladder areas are characterized by important differences among trigone, detrusor and neck, the first showing a different pattern of expression compared to the other parts. Further, there are evidences of both density and subtype gender-dependent expressions. α1 ARs expression in prostate and detrusor is a widely investigated area of research, mainly due to the clinical impact of benign prostatic hyperplasia (BPH). Urethra has not been well studied in human, although it plays a role in the control of continence.

Studies carried out on α1 AR subtype expression in the UT indicate that, although the presence of each subtype is observed, α1A firstly and then α1D ARs seem to be more expressed than α1B ARs. Thus, drugs that demonstrate high α1A/D AR selectivity have drawn the researchers’ attention. As it relates specifically to the α1 AR antagonists used in the treatment of lower UT symptoms, the concept of uroselectivity has been operationally defined; indeed, in a number of recent publications uroselectivity has been defined as the degree to which a given compound inhibits norepinephrine-induced increase in urinary muscle contractions and/or its propensity to generate unwanted cardiovascular effects, such as decreases in blood pressure.

Alpha1-, alpha2- and beta-adrenoceptors in the urinary bladder, urethra and prostate

1 We have systematically reviewed the presence, functional responses and regulation of alpha(1)-, alpha(2)- and beta-adrenoceptors in the bladder, urethra and prostate, with special emphasis on human tissues and receptor subtypes. 2 Alpha(1)-adrenoceptors are only poorly expressed and play a limited functional role in the detrusor. Alpha(1)-adrenoceptors, particularly their alpha(1A)-subtype, show a more pronounced expression and promote contraction of the bladder neck, urethra and prostate to enhance bladder outlet resistance, particularly in elderly men with enlarged prostates. Alpha(1)-adrenoceptor agonists are important in the treatment of symptoms of benign prostatic hyperplasia, but their beneficial effects may involve receptors within and outside the prostate. 3 Alpha(2)-adrenoceptors, mainly their alpha(2A)-subtype, are expressed in bladder, urethra and prostate. They mediate pre-junctional inhibition of neurotransmitter release and also a weak contractile effect in the urethra of some species, but not humans. Their overall post-junctional function in the lower urinary tract remains largely unclear. 4 Beta-adrenoceptors mediate relaxation of smooth muscle in the bladder, urethra and prostate. The available tools have limited the unequivocal identification of receptor subtypes at the protein and functional levels, but it appears that the beta(3)- and beta(2)-subtypes are important in the human bladder and urethra, respectively. Beta(3)-adrenoceptor agonists are promising drug candidates for the treatment of the overactive bladder. 5 We propose that the overall function of adrenoceptors in the lower urinary tract is to promote urinary continence. Further elucidation of the functional roles of their subtypes will help a better understanding of voiding dysfunction and its treatment.

Use of sympathetic alpha antagonists in the management of pediatric urologic disorders

PURPOSE OF REVIEW

To update the physician regarding the use of alpha-adrenergic antagonists in the management of various pediatric urologic problems.

RECENT FINDINGS

The use of alpha-adrenergic antagonist for the treatment of pediatric urologic disorders has expanded greatly over the past decade. This review summarizes the current use of these medications in the treatment of pediatric voiding dysfunction, neurogenic bladder, chronic lower urinary tract symptomatology, idiopathic urethritis, and the passage of ureteral calculi.

SUMMARY

Currently alpha antagonist therapy although not useful in the primary treatment of voiding dysfunction is equivalent in potency to biofeedback therapy for the treatment of recalcitrant voiding dysfunction. In the management of neurogenic bladder and chronic lower urinary tract symptomatology, alpha antagonists working alone or in conjunction with anticholinergic medications will improve clinical symptoms, increase bladder compliance, and decrease detrusor instability. In addition, alpha antagonists may decrease the intensity and duration of symptoms in patients with idiopathic urethritis. Compared with placebo, alpha-adrenergic antagonists will also aid significantly in the spontaneous passage of distal ureteral calculi, thereby reducing the need for surgical intervention and analgesia. The findings noted above significantly expand the clinical usefulness of alpha antagonist therapy within the field of pediatric urology.

Improvement of bladder storage function by α1-blocker depends on the suppression of C-fiber afferent activity in rats

AIMS

Alpha1-blockers improve voiding symptoms through the reduction of prostatic and urethral smooth muscle tone; however, the underlying mechanism of improvement of storage symptoms is not known. Using a rat model of detrusor overactivity caused by cerebral infarction (CI), we undertook the present study to determine whether the effect of an alpha1-blocker, naftopidil, is dependent on the suppression of C-fiber afferents.

METHODS

To induce desensitization of C-fiber bladder afferents, we injected resiniferatoxin (0.3 mg/kg, RTX) sub-cutaneously to female Sprague-Dawley rats 2 days prior to left middle cerebral artery occlusion (MCAO) (RTX-CI rats). As controls we used rats without RTX treatment (CI rats). MCAO and insertion of a polyethylene catheter through the bladder dome were performed under halothane anesthesia. We investigated the effects on cystometrography (CMG) of intravenous (i.v.), intracerebroventricular (i.c.v.), or intrathecal (i.t.) administration of naftopidil in conscious CI rats.

RESULTS

Bladder capacity (BC) was markedly reduced after MCAO in both RTX-CI and CI rats. I.v. administration of naftopidil significantly increased BC in CI rats without an increase in residual volume, but it had no effects on BC in RTX-CI rats. I.t. administration of naftopidil significantly increased BC in CI but not in RTX-CI rats.

CONCLUSIONS

These results suggest that naftopidil has an inhibitory effect on C-fiber afferents in the lumbosacral spinal cord, improving BC during the storage phase.

Combined use of alpha-adrenergic and muscarinic antagonists for the treatment of voiding dysfunction

PURPOSE

We provide an overview of the medical literature supporting the combined use of muscarinic and alpha-adrenergic antagonist therapy for the treatment of voiding dysfunction.

MATERIALS AND METHODS

The MEDLINE database (1966 to 2004) of the United States National Library of Medicine was searched for pertinent studies.

RESULTS

Although the mechanism of action of alpha-adrenergic antagonist therapy for voiding dysfunction has traditionally been assumed to be relaxation of the periurethral, prostatic and bladder neck smooth muscle, substantial evidence supports action at extraprostatic sites involved in micturition, including the bladder dome smooth muscle, peripheral ganglia, spinal cord and brain. Likewise the mechanism of action of anticholinergic therapy has been traditionally assumed to be inhibition of the M3 muscarinic receptor subtypes that mediate normal bladder contractions. However, M2 receptor mediates hypertrophied bladder contractions and there is evidence for an M2 component to the suprasacral control of voiding.

CONCLUSIONS

Based on the physiology of alpha-adrenergic and muscarinic receptors the inhibition of each one would be expected to be more beneficial than that of either alone because they would work on 2 components of detrusor function. Patients who would likely benefit from this combination therapy are men with lower urinary tract symptoms, women with urgency/frequency syndrome (overactive bladder), patients with uninhibited bladder contractions due to neurogenic bladder, and patients with pelvic pain and voiding symptoms, ie interstitial cystitis and chronic prostatitis/chronic pelvic pain syndrome.

Evidence for the presence of alpha1 adrenoceptor subtypes in the human ureter

AIM

Several studies have proposed a role for alpha1 adrenoceptors (ARs) in ureteral physiology, indicating that they are present in the ureter; however, few studies have been done to identify alpha1 AR subtypes present in this area. Thus, this study was carried out to characterize the alpha1 AR subtype gene and protein expression in proximal, medial, and distal region of the human ureter.

METHODS

Molecular characterization of alpha1 AR subtypes were analyzed by semi-quantitative RT-PCR. alpha1 AR protein expression was studied by saturation binding curves and by competition binding curves with selective antagonists. Analysis of data was performed using the GraphPad PRISM 4 software.

RESULTS

Analysis of saturation binding curves revealed a heterogeneous distribution of alpha1 AR binding sites, the B(max) for the distal ureter was indeed 52.5 +/- 5.4 fmol/mg prot, while a lower similar density of alpha1 ARs was demonstrated in the medial (25.2 +/- 1.7 fmol/mg prot) and proximal (23.4 +/- 0.4 fmol/mg prot) ureters. Molecular and pharmacological characterization of alpha1 AR subtypes indicated that each receptor was present, although with differences in terms of the amount expressed.

CONCLUSIONS

Human ureter was endowed with each alpha1 AR subtype, although alpha1D and alpha1A ARs were prevalent over alpha1B ARs. Radioligand binding results revealed that there were no significant differences in the K(d) between ureteral regions, while a heterogeneous distribution of alpha1 AR binding sites was detected, with the highest density of alpha1 ARs in the distal ureter and a lower similar density in the medial and proximal ureters.

α1-Adrenergic Receptors and Their Inhibitors in Lower Urinary Tract Symptoms and Benign Prostatic Hyperplasia

PURPOSE

We provide a comprehensive overview of the role of alpha1-adrenergic receptors (alpha1ARs) as critical mediators of lower urinary tract symptoms (LUTS) and pathophysiology in benign prostatic hyperplasia (BPH), and we review the pharmacological antagonists of alpha1ARs.

MATERIALS AND METHODS

A review was performed of pertinent studies in the literature relating to the pathophysiology of LUTS and BPH, focusing on the role of alpha1ARs, and of clinical trial and practice data evaluating the different agents that inhibit these receptors.

RESULTS

Further characterization of the alpha1AR gene family indicates that 3 receptor subtypes exist in humans. Their different distribution between urinary tract and cardiovascular tissues has provided a strategy for the development of improved therapeutic agents. Since excessive activity of the alpha1aAR and alpha1dAR subtypes appears to be a common feature in symptomatic BPH and alpha1aARs are enriched in prostatic tissue, drugs that demonstrate high alpha1aAR selectivity have attracted attention. Tamsulosin, which has high affinity for alpha1aAR and alpha1dAR subtypes but not for alpha1bAR, shows efficacy similar to the nonsubtype selective agents terazosin and doxazosin. It is associated with fewer cardiovascular side effects, although it has some ejaculatory side effects. The nonsubtype selective agent alfuzosin also demonstrates efficacy and offers an enhanced side effect profile, particularly minimizing hypotension. Other agents with super selective specificity for the alpha1aAR subtype are under investigation.

CONCLUSIONS

Further advances in the treatment of LUTS associated with BPH may depend not only on receptor subtype selectivity, but also on other pharmacokinetic and pharmacodynamic factors.

Tamsulosin: Efficacy and Safety in Patients With Neurogenic Lower Urinary Tract Dysfunction Due to Suprasacral Spinal Cord Injury

PURPOSE

We evaluated the efficacy and safety of tamsulosin in patients with neurogenic lower urinary tract dysfunction secondary to suprasacral spinal cord lesions in a 4-week randomized controlled trial (RCT) followed by a 1-year, open label, long-term study.

MATERIALS AND METHODS

A total of 263 patients were randomized to 4-week double-blind therapy with placebo, or 0.4 or 0.8 mg tamsulosin once daily. Of these, 244 patients completed the RCT, 186 continued long-term tamsulosin therapy (0.4 or 0.8 mg once daily) and 134 completed 1-year treatment. The primary efficacy parameter was maximum urethral pressure (MUP).

RESULTS

Although the mean decrease in MUP at 4 weeks in the RCT did not reach statistical significance over the placebo, it was more pronounced with 0.4 (-12.2 cm H2O or -10%) and 0.8 mg (-9.6 cm H2O or -9%) tamsulosin than placebo (-6.5 cm H2O or -3%). In the long-term study there was a statistically significant mean decrease in MUP (-18.0 cm H2O, p <0.001 or -15%) from baseline to end point. In the long-term study tamsulosin also decreased maximum urethral closure pressure, improved several cystometry parameters related to bladder storage and emptying, and increased to a statistically significantly degree, from baseline to end point, mean voided volume based on the micturition diary. There was statistically significant improvement for the International Prostate Symptom Score Quality of Life, as well as several questions about symptoms related to urinary leakage, and 1 question on bladder emptying and frequency, bother and severity of symptoms of autonomic dysreflexia. Finally, 71% of patients improved according to investigators (44% slightly and 27% much improved). Both doses were effective and well tolerated.

CONCLUSIONS

Long-term tamsulosin treatment (0.4 and 0.8 mg once daily) seems to be effective and well tolerated in patients with neurogenic lower urinary tract dysfunction. The results suggest that it improves bladder storage and emptying, and decreases symptoms of autonomic dysreflexia.

The use of alpha1-adrenoceptor antagonists in lower urinary tract symptoms: beyond benign prostatic hyperplasia

The first empirical use of alpha(1)-adrenoceptor antagonists in urology occurred about 25 years ago in patients with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH), or LUTS/BPH. Today, many randomized, controlled trials have provided evidence for the efficacy and tolerability of alpha(1)-adrenoceptor antagonists in LUTS/BPH, and they are the most frequently used initial treatment option for this cause of LUTS. For many years, alpha(1)-adrenoceptor antagonists have also been used empirically in other types of lower urinary tract dysfunction (LUTD), such as chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and neurogenic LUTD (NLUTD). Several investigators have shown that alpha(1)-adrenoceptor antagonists may be useful in patients with CP/CPPS. This was recently confirmed by a 6-week, double-blind, placebo-controlled pilot study evaluating the efficacy and safety of tamsulosin in 58 CP/CPPS patients. Further well-designed and -powered research into the use of alpha(1)-adrenoceptor antagonists in patients with CP/CPPS is currently ongoing. Several small-scale predominantly open-label studies have suggested that alpha(1)-adrenoceptor antagonists may be of benefit in patients with NLUTD. Data from 2 recent large-scale studies with tamsulosin in patients with NLUTD caused by suprasacral spinal cord injury suggest that long-term tamsulosin treatment improves bladder storage and emptying and also reduces symptoms of autonomic dysreflexia. Tamsulosin has also shown promise in ameliorating (early) storage symptoms and urinary retention associated with transurethral microwave thermotherapy, external-beam radiotherapy, and brachytherapy. In BPH patients presenting with the ultimate form of LUTS-acute urinary retention-treatment with tamsulosin before catheter removal results in a higher success rate of catheter-free voiding. Finally, it seems that alpha(1)-adrenoceptor antagonists may reduce the occurrence of urinary retention after (general) surgery. We can therefore conclude that alpha(1)-adrenoceptor antagonists, such as tamsulosin, may be useful for treating men with LUTS beyond BPH.

Alfuzosin in the treatment of high leak-point pressure in children with neurogenic bladder

OBJECTIVE

To decrease the detrusor leak-point pressure (LPP) of > 40 cmH2O in children with a neurogenic bladder, using the alpha1-adrenergic blocking agent alfuzosin.

PATIENTS AND METHODS

Videocystometry was used to measure the detrusor LPP and several other variables before and 3 weeks after the oral administration of alfuzosin (2.5-7.5 mg/day) in 17 children (mean age 6.3 years) with an upper motor neurone lesion.

RESULTS

The mean (sd) detrusor LPP decreased from 68 (37) to 46 (31) cmH2O (P < 0.01), reflex volume (defined as the volume at the first uninhibited bladder contraction of > 15 cmH2O) increased from 78 (69) to 112 (118) mL (+ 44%), bladder compliance increased from 9.3 (6.1) to 19.6 (14.6) mL/cmH2O (+ 111%), maximal vesical pressure decreased from 84 (40) to 70 (47) cmH2O (- 17%), and the mean number of uninhibited bladder contractions decreased from 6.3 to 3.5 (- 44%). The therapy was well tolerated; side-effects were rare and not severe. Intermittent catheterization could be avoided in six children.

CONCLUSION

Alfuzosin decreases the detrusor LPP in children with a neurogenic bladder caused by an upper motor neurone lesion, significantly and therapeutically, and should be considered as an alternative or addition to intermittent catheterization and anticholinergic drugs in selected patients.

Effect of bilateral hypogastric nerve transection on voiding dysfunction in rats with spinal cord injury

We determined if bilateral section of the hypogastric nerves (HGN), which provide the major sympathetic input to the urinary bladder neck/proximal urethra, could improve voiding by reducing urethral resistance in conscious, female spinal-cord-injured (SCI) rats 2-3 weeks after T(7-9) transection of the spinal cord. Cystometry was performed in animals with HGN intact and with HGN sectioned bilaterally 1-2 h before the experiment. Residual volume (RV), volume threshold for inducing micturition (VT), maximal voiding pressure, and bladder compliance were significantly lower (71, 35, 33, and 31%, respectively) in SCI rats with sectioned HGN than in rats with intact HGN, whereas voided volume (VV), pressure threshold for micturition, and bladder contraction duration (BCD) in the two groups were similar. Voiding efficiency (VE) in the HGN-sectioned group was 36% greater than that in the HGN-intact group. Antagonists for AMPA and NMDA glutamatergic receptors (LY215490 and MK-801, respectively) were administered to rats with sectioned HGN, to determine if activity in the HGN contributes to the previously reported inhibitory effects of these drugs, on voiding function after SCI. MK-801 (3 mg/kg iv) significantly reduced VV (75%) and VE (85%) and increased RV (8-fold), VT (87%), and bladder compliance (60%), whereas LY215490 (10 mg/kg iv) significantly increased VT and BCD by 15 and 19%, respectively. It is concluded that bilateral section of HGN reduces voiding dysfunction in the SCI rat but does not alter the effects of AMPA and/or NMDA glutamatergic receptor antagonists on the micturition reflex in the SCI rat. Thus the effects of these drugs are not dependent on changes in activity of sympathetic axons in the HGN.

Urinary tract infections in patients with spinal cord lesions: treatment and prevention

Even though the mortality due to urinary tract complications has decreased dramatically during the last decades in individuals with spinal cord lesions (SCL), urinary tract infections (UTI) still cause significant morbidity in this population. Complicated UTI are caused by a much wider variety of organisms in individuals with SCL than in the general population and are often polymicrobial. Escherichia coli, Pseudomonas spp., Klebsiella spp., Proteus spp., Serratia spp., Providencia spp., enterococci, and staphylococci are the most frequently isolated bacteria in urine specimens taken from individuals with SCL. There is no doubt that the greatest risk for complicated UTI in these individuals is the use of an indwelling catheter. Intermittent catheterisation during the rehabilitation phase has been shown to lower the rate of UTI, and virtually eliminate many of the complications associated with indwelling catheters. Persons with SCL should only be treated for bacteriuria if they have symptoms. Generally, it is advisable to use antibacterial agents with little or no impact on the normal flora. Single agent therapy - in accordance with antimicrobial susceptibility test - is preferred. We advise extending treatment to at least 5 days, and in those with reinfection or relapsing UTI, at least 7 to 14 days, depending on the severity of the infection. The diagnosis of structural and/or functional risk factors is essential in order to plan an optimal treatment for UTI in individuals with SCL, which should include treatment of simultaneously occurring predisposing factors. The treatment of structural risk factors follows general urological principles, aiming for sufficient outlet from the bladder with minimal residual urine and low pressure voiding. For prevention of UTI, general cleanliness and local hygiene should be encouraged. If the patient has a reinfection or relapsing symptomatic UTI, it is important to check for inadequately treated infection and complications, which need special attention, in particular residual urine and urinary stones. No reliable evidence exists of the effectiveness of cranberry juice and other cranberry products. Prophylactic antibacterials should only be used in patients with recurrent UTI where no underlying cause can be found and managed, and in particular if the upper urinary tract is dilated. Antibacterials should not be used for the prevention of UTI in individuals with SCL and indwelling catheters. However, the use of prophylactic antibacterials for individuals with SCL using intermittent catheterisation or other methods of bladder emptying is controversial.

Smooth muscle and parasympathetic nerve terminals in the rat urinary bladder have different subtypes of alpha(1) adrenoceptors

Neurally evoked contractions and release of (3)H- acetylcholine (ACh) during electrical field stimulation were measured in rat urinary bladder strips. The alpha(1) agonist phenylephrine (PE, 2-8 microM) increased the amplitude of neurally evoked contractions, facilitated the release of ACh and increased the baseline tone of the bladder strips. The PE-induced facilitation of the contractions did not significantly change during a prolonged exposure to PE (120 min), whereas the PE-induced rise in baseline tone gradually decreased to 65% of the initial value. Low concentrations of specific alpha(1A) antagonists, 5-methyl urapidil (5-MU), REC15/2739 and WB-4101 competitively inhibited the facilitation of the neurally-evoked contractions (pA(2:) 8.77; 9.59 and 9.62, respectively), whereas higher concentrations of 5-MU (IC(50): 48 nM) were required to suppress the PE-rise in baseline. WB-4101 (100 microM) inhibited the PE-induced facilitation of ACh release. The irreversible alpha(1B) antagonist chloroethyl-clonidine (CEC, 10-50 microM) inhibited the PE-evoked rise in base line tone, but did not affect the PE-induced facilitation of the neurally evoked contractions nor the facilitation of ACh release. However, CEC increased the area and amplitude of the neurally-evoked contractions by 261+/-33 and 47.2+/-8.4%, respectively. Atropine significantly inhibited the CEC evoked increase in area and amplitude of the electrically evoked contractions (76.5+/-4.8 and 40.8+/-3%, respectively) indicating that CEC facilitated the cholinergic responses of the electrically stimulated bladder strips. It is concluded that alpha(1A) and CEC sensitive alpha(1B) and/or alpha(1D) adrenoceptors are expressed in the rat bladder in different locations. On the cholinergic nerve terminals alpha(1A) adrenoceptors mediate prejunctional facilitation, whereas postjunctional alpha(1B)/alpha(1D) adrenoceptors mediate smooth muscle contraction.

Prospective study comparing hyoscyamine, doxazosin, and combination therapy for the treatment of urgency and frequency in women

Anticholinergics are commonly used for the treatment of frequency, urgency, and urge incontinence in women. Alpha-blockers have been shown to have a modulating effect on bladder smooth muscle but are not commonly used clinically for this indication. To evaluate the clinical effectiveness of each treatment as well as the combination therapy, we performed an open prospective study comparing these agents. Between September 1994 and October 1995, 34 women aged 28-91 (mean age, 62) received either 0.375 mg of sustained-release hyoscyamine twice a day or 2 mg doxazosin QHS prior to being crossed over to the other drug and/or the combination. Symptoms were assessed using an expanded American Urological Association (AUA) symptoms score, which included questions regarding incontinence at completion of each therapeutic phase. Evaluation included 6-channel urodynamics. All three therapies were noted to be effective in reducing AUA symptom scores. By urodynamic evaluation, a greater percentage of patients with increased voiding pressures or decreased compliance responded to doxazosin than hyoscyamine. Side effects were noted to be less prevalent with doxazosin than with the other therapies. There appears to be a significant role for alpha-blockers in the treatment of voiding symptoms in women.

Phenoxybenzamine in the management of neuropathic bladder following spinal cord injury

BACKGROUND

The present study aims to show the clinical and urodynamic effects of phenoxybenzamine on the neuropathic bladder of spinal cord-injured patients who failed to be free of catheter by attaining satisfactory voiding function, despite initial bladder training.

METHODS

Forty-six spinal cord-injured patients were subjected to pharmacological manipulation with phenoxybenzamine. It was used as an adjunct in the management of neuropathic bladder dysfunction that caused failure of the bladder to empty, by tapping or crede to achieve satisfactory residual urine volume of < 100 mL. Phenoxybenzamine was started with a dose of 10 mg daily, increased by 10 mg every 3 days to a dose of 30 mg daily; this was maintained from 3 weeks to 6 months (mean: 39 days). The pre-treatment residual urine volume ranged between 100 and 1050 mL (mean: 360 mL). Follow-up periods ranged between 12 and 36 months (mean: 16 months).

RESULTS

Five patients (11%) were excluded due to either inadequate treatment or inadequate follow-up. Nineteen patients (41%) with reflex (upper motor neurone) bladders showed improvement of bladder evacuation. There was a reduction of the maximum urethral closure pressure, which ranged between 10 and 32 cm of water (mean: 22 cm). Twenty-two patients (48%) did not respond, requiring other measures to be taken which included transurethral surgery (n = 19). Nine of the failures involved areflex (lower motor neurone) bladders, and seven failures involved reflex bladders with an extremely tight outlet and urethral closure pressure of > 50 cm of water. Six failures involved reflex bladders that were lacking strong enough detrusor contractions to attain a balanced bladder responsive to abdominal tapping; response was achieved by administration of a parasympatheticomimetic drug. Neuropathic bladders with uninhibited detrusor contractions responded well to phenoxybenzamine.

CONCLUSIONS

Phenoxybenzamine proved useful in reducing bladder outlet resistance after spinal cord injury, provided that detrusor bladder contractions were present. It is useful in controlling detrusor-sphincter dyssynergia and autonomic hyperreflexia. It was not useful in areflex bladders, perhaps due to the development of spasticity of the striated muscle component of the external sphincter. The presence of bladder neck (internal sphincter) dysfunction may modify or abolish its effect.

alpha-Adrenergic blockade in children with neuropathic and nonneuropathic voiding dysfunction

PURPOSE

Inadequate bladder emptying is a common urinary dysfunction in children. The role of alpha-blockers for managing bladder outlet obstruction remains relatively unexplored in children. Because of the well established impact of alpha-blocker therapy in men, we investigated its use for treating inadequate bladder emptying in the pediatric population.

MATERIALS AND METHODS

We treated 17 children 3 to 15 years old with documented poor bladder emptying of various etiologies, including dysfunctional voiding, the Hinman syndrome, the lazy bladder syndrome, posterior urethral valves, myelomeningocele and the prune-belly syndrome, using the alpha-1 adrenergic receptor antagonist, doxazosin. The initial dose of 0.5 to 1.0 mg. nightly was increased according to patient response and as tolerated. Patients were followed weekly to monthly by symptomatic history, and urine flow and/or post-void residual urine volume measurement. Two patients with neurogenic bladder were also followed with cystometrography and leak point pressure determination.

RESULTS

Bladder symptomatology and/or emptying improved in 14 patients (82%). Ten patients had decreased post-void residual urine during treatment and in 3 uroflowmetry showed increased maximum flow. Two patients with neuropathic bladder secondary to myelomeningocele had decreased leak point pressure on alpha-blocker therapy and in 2 with a history of posterior urethral valves new onset bilateral hydronephrosis completely resolved. Only 1 patient had mild postural hypotension, which resolved with dose reduction.

CONCLUSIONS

Selective alpha-blocker therapy seems to be well tolerated in children and appears effective for improving bladder emptying in various pediatric voiding disorders at short-term followup. Long-term followup and further investigation are warranted to validate the potential role of alpha-blocker therapy in pediatric urinary dysfunction.

Alpha-adrenoceptor antagonists in neurogenic lower urinary tract dysfunction

Lower urinary tract dysfunction is common in patients with a variety of neurological diseases, and may lead to debilitating symptoms and serious complications. Any treatment that can reduce these symptoms or complications is welcome. In many trials, alpha-adrenoceptor antagonists (alpha blockers) have been evaluated as treatment for neurogenic lower urinary tract dysfunction; however, these have generally been small and often nonrandomized, uncontrolled studies. Existing evidence suggests that alpha blockers may have a small but useful effect in the facilitation of storage and emptying, and in the prevention of autonomic dysreflexia. Better understanding of lower urinary tract physiology and larger clinical trials with longer follow-up will hopefully clarify the role of alpha blockers in the future.

Alpha1-adrenergic receptors in human spinal cord: specific localized expression of mRNA encoding alpha1-adrenergic receptor subtypes at four distinct levels

alpha1-Adrenergic receptors (alpha1ARs) are important in lower urinary tract syndromes such as benign prostatic hypertrophy and bladder irritability. Spinal cord alpha1ARs have been postulated to play a role in modulating these diseases, yet alpha1AR subtype (alpha1a, alpha1b, alpha1d) neuronal localization in human spinal cord has not been described. We therefore tested the hypothesis that alpha1AR subtype distribution varies according to specific spinal cord tract and level. In situ hybridization was performed to identify cell bodies containing alpha1AR subtype mRNA at four levels of human spinal cord (cervical enlargement, thoracic, lumbar, sacral). alpha1AR mRNA is present in ventral gray matter only (ventral>dorsal; sacral>lumbar=thoracic>cervical). Signaling cell bodies were detected in anterior horn motor neurons at all levels; dorsal nucleus of Clarke and intermediolateral columns in cervical enlargement, thoracic and lumbar spinal cord regions; and parasympathetic nucleus in sacral spinal cord. Although all three alpha1AR subtypes are present throughout human spinal cord, alpha1d mRNA predominates overall. If confirmed at a protein level, these findings may contribute to the development of new therapeutic strategies in the treatment of several human diseases.

Neurophysiology of micturition and continence in women

Micturition and continence involve the coordination of complex neural events between the central and peripheral nervous systems. An understanding of these events provides a foundation for the treatment of voiding disorders in women such as stress urinary incontinence, urge incontinence and interstitial cystitis. The purpose of this paper is to comprehensively review the neuroanatomy, neurophysiology and neuropharmacology of micturition and continence. However, a brief section discussing clinical correlations will follow each of these topics to help integrate the basic science with clinical observations.

Neurophysiology of micturition and continence

This article reviews the neuroanatomy, neurophysiology, and neuropharmacology involved in micturition and continence. Knowledge of these topics helps the clinician diagnose and treat voiding disorders that are caused by disease, trauma, drugs, and aging.

Effect of intravenous alfuzosin on urethral pressure in patients with neurogenic bladder dysfunction. DORALI Study Group

In order to assess the ability of a single intravenous (i.v.) injection of alfuzosin, a selective alpha-1 blocker, in reducing high urethral tone in patients with symptomatic neurogenic bladder dysfunction (NBD), 163 patients (mean maximal urethral pressure [MUP] 108 +/- 46 cm H2O) were enrolled in a double-blind, placebo-controlled, parallel-group trial and were randomly allocated to receive 0.5 mg (n = 45), 1 mg (n = 41), 2 mg (n = 39) alfuzosin or placebo (n = 38). The decrease in MUP was dose-dependent and statistically significant (P < or = 0.05) for 1 and 2 mg alfuzosin (respectively, 43 +/- 28 cm H2O and 46 +/- 27 cm H2O decreases vs. baseline) in comparison with placebo (23 +/- 30 cm H2O). The 2 mg dose level was the most effective leading to a > or = 30 or 50% decrease in MUP in, respectively, 69 and 44% of patients. The safety of all three alfuzosin dose levels was satisfactory and comparable to placebo. I.v. alfuzosin induces, in a dose-related manner, a clinically significant decrease in urethral pressure in patients with NBD and high urethral tone, and may be safely used as a pharmacological test as part of an urodynamic investigation.

Contribution of alpha- and beta- adrenoceptors and neuropeptide-Y to autonomic dysreflexia

Modest increases in urinary bladder pressure result in acute hypertensive episodes in humans with spinal cord lesions above T5. The underlying mechanisms of this condition, referred to as autonomic dysreflexia, are not well understood. The aim of this study was to characterize the contribution of alpha- and beta-adrenoceptors as well as circulating neuropeptide-Y (NPY) to the pressor response to bladder distension in conscious cervical spinal rats. Rats were chronically instrumented with arterial and venous catheters. After 2-3 days, a complete spinal transection (C7) was performed, and the urinary bladder was catheterized: 24 h later, mean arterial pressure (MAP) responses to 5 min bladder distensions (+40) were measured under control conditions and after administration of specific autonomic antagonists. To assess the contribution of alpha and beta adrenergic mechanisms the alpha antagonist prazosin (0.45 mg/kg i.v.) and beta antagonist, propranolol (4 mg/kg i.v.), were administered individually or together. Blood samples were taken before, during and after bladder distension for determination of plasma NPY by radioimmunoassay. The pressor response to bladder distension was approximately 30 mmHg under control conditions. The response was attenuated (-38%), but not abolished, by prazosin. A similar attenuation (-41%) was observed with propranolol. There were no changes in plasma NPY in response to bladder distension. Finally, the pressor response was completely abolished by combined alpha- and beta-adrenergic blockade. These results suggest that autonomic dysreflexia is mediated exclusively by adrenergic receptors in the spinal rat. Moreover, both alpha and beta adrenergic receptors contribute to the pressor response induced by bladder distension in the conscious cervical spinal rat.