A study of human bladder detrusor muscle

Lower Urinary Tract Symptoms (LUTS) as a New Clinical Presentation of Histamine Intolerance: A Prevalence Study of Genetic Diamine Oxidase Deficiency

Lower urinary tract symptoms (LUTS) are highly prevalent, and their treatment is mainly focused on the control of symptoms. Histamine intolerance (HIT) has been related to a variety of systemic symptoms. DAO deficiency has been identified as a significant factor contributing to histamine intolerance (HIT). Preclinical evidence indicates the involvement of histamine in the lower urinary tract. This study aimed to assess the prevalence of diamine oxidase deficiency (DAO) in a prospective cohort of 100 patients with at least moderate LUTS. A genetic study of four single nucleotide polymorphisms (SNPs) (c.-691G>T, c.47C>T, c.995C>T, and c.1990C>G) was performed. HIT was found in 85.9% of patients. The prevalence of at least one minor allele in the SNPs analyzed was 88%, without gender differences. Storage symptoms were more intense in the presence of HIT as well as asthenia and neurological and musculoskeletal symptoms. The presence of minor alleles of the AOC1 gene was associated with a higher intensity of symptoms. Minor alleles from c.-691G>T and c.47C>T SNPs were also associated with a greater severity of obstructive symptoms. Thirty-one percent of patients presented the four SNPS with at least one associated minor allele. The relationship between HIT and LUTS in a mixed population of men and women found in this study supports further investigations to define the pathophysiology of histamine in LUTS.

The change of signaling pathway on the electrical stimulated contraction in streptozotocin-induced bladder dysfunction of rats

Bladder dysfunction is a common complication of diabetes mellitus (DM). However, there have been a few studies evaluating bladder smooth muscle contraction in DM in the presence of pharmacological inhibitors. In the present study, we compared the contractility of bladder smooth muscle from normal rats and DM rats. Furthermore, we utilized pharmacological inhibitors to delineate the mechanisms underlying bladder muscle differences between normal and DM rats. DM was established in 14 days after using a single injection of streptozotocin (65 mg/kg, intraperitoneal) in Sprague-Dawley rats. Bladder smooth muscle contraction was induced electrically using electrical field stimulation consisting of pulse trains at an amplitude of 40 V and pulse duration of 1 ms at frequencies of 2–10 Hz. In this study, the pharmacological inhibitors atropine (muscarinic receptor antagonist), U73122 (phospholipase C inhibitor), DPCPX (adenosine A₁ receptor antagonist), udenafil (PDE5 inhibitor), prazosin (α₁-receptor antagonist), verapamil (calcium channel blocker), and chelerythrine (protein kinase C inhibitor) were used to pretreat bladder smooth muscles. It was found that the contractility of bladder smooth muscles from DM rats was lower than that of normal rats. In addition, there were significant differences in percent change of contractility between normal and DM rats following pretreatment with prazosin, udenafil, verapamil, and U73122. In conclusion, we suggest that the decreased bladder muscle contractility in DM rats was a result of perturbations in PLC/IP₃-mediated intracellular Ca²⁺ release and PDE5 activity.

The comparative effects of aminoglycoside antibiotics and muscle relaxants on electrical field stimulation response in rat bladder smooth muscle

It has been reported that several aminoglycoside antibiotics have a potential of prolonging the action of non-depolarizing muscle relaxants by drug interactions acting pre-synaptically to inhibit acetylcholine release, but antibiotics itself also have a strong effect on relaxing the smooth muscle. In this study, four antibiotics of aminoglycosides such as gentamicin, streptomycin, kanamycin and neomycin were compared with skeletal muscle relaxants baclofen, tubocurarine, pancuronium and succinylcholine, and a smooth muscle relaxant, papaverine. The muscle strips isolated from the rat bladder were stimulated with pulse trains of 40 V in amplitude and 10 s in duration, with pulse duration of 1 ms at the frequency of 1-8 Hz, at 1, 2, 4, 6, 8 Hz respectively. To test the effect of four antibiotics on bladder smooth muscle relaxation, each of them was treated cumulatively from 1 μM to 0.1 mM with an interval of 5 min. Among the four antibiotics, gentamicin and neomycin inhibited the EFS response. The skeletal muscle relaxants (baclofen, tubocurarine, pancuronium and succinylcholine) and inhibitory neurotransmitters (GABA and glycine) did not show any significant effect. However, papaverine, had a significant effect in the relaxation of the smooth muscle. It was suggested that the aminoglycoside antibiotics have inhibitory effect on the bladder smooth muscle.

The Inhibitory Mechanism of Gentamicin on Electrical Field Stimulation Response in Rat Bladder Smooth Muscle

To see the inhibitory mechanism of gentamicin in response to electrical field stimulation (EFS) using the rat bladder smooth muscle, atropine or guanethidine was treated but had no effect. Methylsergide, a non-selective 5-HT1, 5-HT2 receptor antagonist was also treated but had on effect. Kinase inhibitors, such as chelerythrine (PKC inhibitor), ML-9 (MLCK inhibitor), or Y27632 (rho kinase inhibitor) were pretreated before gentamicin treatment, but did not have effect. For U73122, a phospholipase C (PLC) inhibitor however, the inhibitory effect to gentamicin was significantly attenuated in all frequencies given by the EFS. Therefore gentamicin induced inhibitory effect on EFS response in rat bladder smooth muscle was not mediated by the activation of adrenergic, cholinergic, or serotonergic receptor. The inhibition of gentamicin might be mediated through the PLC dependent pathway, but not through the PKC, MLCK or rho kinase dependent pathway.

Neuroanatomy of the lower urinary tract

The lower urinary tract (LUT), which consists of the urinary bladder and its outlet, the urethra, is responsible for the storage and periodic elimination of bodily waste in the form of urine. The LUT is controlled by a complex set of peripheral autonomic and somatic nerves, which in turn are controlled through neural pathways in the spinal cord and brain. This influence of the central nervous system allows for the conscious control of the bladder, allowing the individual to choose an appropriate place to urinate. Defects in the CNS pathways that control the LUT can lead to incontinence, an embarrassing condition that affects over 200 million people worldwide. As a first step in understanding the neural control of the bladder, we will discuss the neuroanatomy of the LUT, focusing first on the peripheral neural pathways, including the sensory pathways that transmit information on bladder filling and the motoneurons that control LUT muscle contractility. We will also discuss the organization of the central pathways in the spinal cord and brainstem that are responsible for coordinating bladder activity, promoting continuous storage of urine except for a few short minutes per day when micturition takes place. To conclude, we will discuss current studies underway that aim to elucidate the higher areas of the brain that control the voluntary nature of micturition in higher organisms.

beta-Adrenoceptor stimulation of the human urinary bladder in vivo

The effect of beta-adrenorecptor stimulation on the volume of the urinary bladder in 16 neurologically normal humans without symptoms of micturition disturbances was investigated. Terbutaline, a selective beta2-adrenoceptor stimulating agent, was tested in 9 persons and isoprenaline, a general beta-adrenoceptor stimulating agent, was tested in 7 persons. After terbutaline the maximum increase in the bladder volume was 10% and on an average aroung 5%. After isoprenaline the maximum increase in the bladder volume was 15% and on an average around 5%. Terbutaline as well as isoprenaline administration resulted in tachycardia and an increased pulse pressure. The tachycardia was somewhat more marked after isoprenaline. In conclusion, only a small increase in the volume of the urinary bladder was noted after beta-adrenoceptor stimulation in neurologically normal humans without symptoms of micturition disturbances, in contrast to effects achieved in some patients with urgency. Terbutaline seems to have less cardiac effects compared to isoprenaline and is therefore to be preferred when beta-adrenoceptor stimulation is required in patients with urgency.

An evaluation of laparoscopic tissue harvesting for human adult urological smooth muscle physiological experimentation

OBJECTIVE

To evaluate the properties of laparoscopically harvested bladder neck and ureteric smooth muscle, compared with tissue obtained at open surgery.

MATERIALS AND METHODS

Bladder neck was harvested from patients undergoing open (eight) or laparoscopic radical prostatectomy (11). Ureter was obtained from patients undergoing nephrectomy (laparoscopic or open) and cystectomy (open only); obtained openly from 16 and laparoscopically from seven. Muscle strips dissected from these samples were perfused in a Brading-Sibley organ bath, and stimulated using standard agonists (100 micromol/L carbachol for bladder neck, 100 mmol/L KCl-enriched Krebs' solution for ureteric muscle). Tensions produced were recorded using strain gauges and analysed using data-acquisition software. Results were compared by a two-tailed Fisher's exact test to determine significance.

RESULTS

Openly harvested bladder neck muscle strips from six patients showed a measurable response to the standard agonist. Laparoscopically harvested bladder neck strips from only two patients showed any measurable response. Openly harvested ureteric muscle strips from 12 patients responded to K-enriched solution, while one patient's laparoscopically harvested strips responded to stimulation. This difference was significant in both tissue groups separately (P < 0.025). Histological evaluation identified no specific differences between openly and laparoscopically harvested tissue.

CONCLUSION

The yield of smooth muscle available for research is significantly less when the resection is laparoscopic; this might be a result of diathermy damage at a subcellular level. With the increasing use of the laparoscopic approach in urological surgery, the effect on tissue availability for human smooth muscle physiological study is important to researchers in this field.

Treatment of urethral sphincter mechanism incompetence in 11 bitches with a sustained-release formulation of phenylpropanolamine hydrochloride

Between 1995 and 1999, urethral sphincter mechanism incompetence was diagnosed in 11 bitches. They had been treated with phenylpropanolamine hydrochloride at the recommended dose rate, but had shown no response or had become refractory to treatment. They were treated with phenylpropanolamine hydrochloride in a sustained-release formulation combined with diphenylpyraline hydrochloride. The urinary incontinence resolved fully in six of the bitches, two of which remained continent after the treatment was withdrawn; two showed a marked improvement on daily treatment, but the other three bitches failed to respond and underwent colposuspension.

Influence of 5-hydroxytryptamine and the effect of a new serotonin receptor antagonist (sarpogrelate) on detrusor smooth muscle of streptozotocin-induced diabetes mellitus in the rat

BACKGROUND

We evaluated the changes in the response of detrusor muscle to 5-hydroxytryptamine (5-HT; serotonin) and its receptor mechanisms in pathologic bladder of diabetes mellitus rats.

METHODS

Eight-week-old male Wistar rats were given an intraperitoneal injection of streptozotocin (STZ, 60 mg/kg) in order to induce diabetes mellitus (4 weeks' duration). The bladder strips (10 x 2 mm) were subjected to a tension of 1.0 g in organ baths for the measurements of isotonic contractile responses to 5-HT or relaxation responses to 5-HT antagonists.

RESULTS

Bladder strips from STZ-diabetic rats responded to 5-HT with greater contractions than did those of control rats, given vehicle alone. However, bladder strip weights gradually increased in the STZ-diabetic rats as compared with control rats and when the contractile response to 5-HT was expressed as a percentage of the response to 10(-1) mol/L KCl there was no statistically significant difference between the groups. In both control and diabetic rats, the 5-HT3 selective antagonist did not markedly inhibit the contractile response to 5-HT. In contrast, the 5-HT2A selective antagonist inhibited the contractile response to 5-HT in a dose-dependent manner.

CONCLUSIONS

These results suggest that the increased contractile response to 5-HT in diabetic rats' bladder is related to smooth muscle hypertrophy and/or hyperplasia and indicate that this effect is mediated by activation of 5-HT2A receptors.

Changes in bladder tone during filling: pharmacological aspects

The mechanism by which the bladder maintains a low pressure during filling has not yet been established. Myogenic and neural factors have been suggested, although their relative importance has not been settled. There is an ongoing thoracolumbar sympathetic outflow to the lower urinary tract during filling, and noradrenaline, released from adrenergic nerves and acting through stimulation of beta-adrenoceptors (beta 2 and beta 3), may relax the bladder, due to a relative dominance of beta- over alpha-adrenoceptors in the detrusor. Non-adrenergic, non-cholinergic mediators, such as nitric oxide and vasoactive intestinal polypeptide have been suggested to relax the detrusor during filling; there is no compelling evidence to support these proposals. Unidentified relaxant factors may be released from the bladder. Their existence and possible importance need to be further documented. Although it is widely accepted that there is no sacral parasympathetic outflow to the bladder during filling, antimuscarinic drugs increase, and anticholinesterase inhibitors decrease bladder capacity, suggesting an ongoing acetylcholine (ACh) mediated stimulation of detrusor tone. If this is correct, agents inhibiting ACh release should be expected to contribute to bladder relaxation during filling. Inhibition of ACh release can be obtained by stimulation of various receptors on cholinergic nerves, including alpha 2-adrenoceptors, receptors for neuropeptide Y and galanin, or by antagonism of neuronal 5-HT4 receptors. Whether any of these mechanisms is of importance for bladder relaxation during filling, or whether they can be targets for pharmacological therapeutic interventions, remains to be established.

In vitro responses of detrusor smooth muscle to stretch and relaxation

In vitro studies subjecting detrusor smooth muscle to stretch and relaxation support the concept that bladder tonus and accommodation result from physical properties of the bladder wall and are not dependent upon neural activity. The properties of automaticity, hysteresis and length/tension relationships of smooth muscle seen clinically and in vivo are also seen in vitro.

Effect of choline ester analogues, noradrenaline and nifedipine on normal and hypertrophied human urinary bladder detrusor muscle

1. Acetylcholine, bethanechol, carbachol and propionylcholine were all agonists of normal human detrusor smooth muscle. The order of potency was found to be carbachol > acetylcholine > bethanachol > propionylcholine. 2. In hypertrophied detrusor smooth muscle carbachol was more potent than acetylcholine, but hypertrophied detrusor preparations were less sensitive to carbachol than normal detrusor smooth muscle. 3. Noradrenaline had no direct effect on either normal or hypertrophied detrusor muscle, but it had a reversible inhibitory effect on the spontaneous contractile activity of normal detrusor preparations. Hypertrophied detrusor preparations usually lacked such spontaneous activity. 4. In calcium-free saline, agonist-induced responses of both normal and hypertrophied detrusor muscle were dramatically reduced indicating that choline ester activity in the muscles was strongly dependent upon extracellular calcium. 5. Nifedipine at 10(-5) mol l-1 inhibited acetylcholine responses and K(+)-induced contractures of both normal and hypertrophied detrusor muscles. Acetylcholine-induced responses of normal detrusor preparations were much more sensitive to inhibition by nifedipine than were the responses of hypertrophied detrusor muscle. 6. The properties and densities of both the muscarinic cholinoreceptors and calcium channels appear to have been altered by the hypertrophic response secondary to benign prostatic hyperplasia.

Neural 5-HT4 receptors in the human isolated detrusor muscle: effects of indole, benzimidazolone and substituted benzamide agonists and antagonists

1. In strips of human isolated detrusor muscle, the 5-hydroxytryptamine (5-HT) receptor (5-HT4) that mediates facilitation of neuromuscular cholinergic transmission was further characterized by using 5-HT and a series of ligands known for their 5-HT4 agonist (5-methoxytryptamine: 5-MeOT, cisapride, (R,S)-zacopride, BIMU 8) or antagonist (RS 23597, GR 125487, DAU 6285) properties. 2. In the presence of methysergide (1 microM) and ondansetron (3 microM) to isolate pharmacologically the 5-HT4 receptors, 5-HT (0.3 nM-1 microM), 5-MeOT (10 nM -30 microM), BIMU 8 (10 nM-3 microM), cisapride (0.1-10 microM) and (R,S)-zacopride (0.1-30 microM) potentiated cholinergic contractions to electrical field stimulation in a concentration-dependent manner. RS 23597 (10 nM-10 microM), a competitive 5-HT4 receptor antagonist in other systems, also showed agonist properties. The following rank order of potency as an agonist was obtained: 5-HT (pEC50 = 8.0) > RS 23597 (7.0) = BIMU 8 (6.9) > or = cisapride (6.6) > 5-MeOT (6.0) > or = (R,S)-zacopride (5.7). Relative to 5-HT (intrinsic activity = 1), 5-MeOT acted as a full agonist (1.03), while BIMU 8 (0.76), (R,S)-zacopride (0.61), RS 23597 (0.60) and cisapride (0.41) behaved as partial agonists. 3. The potentiation by 5-HT was competitively antagonized by the selective 5-HT4 receptor antagonist GR 125487 (0.3-3 nM) with a pA2 estimate of 9.75 (Schild slope of 1.09), and by DAU 6285 (1 microM; pK3 = 6.45). Additionally, GR 125487 (3 nM) antagonized the responses to 5-MeOT (pKB = 9.72) and reversed the potentiation induced by RS 23597. As an antagonist, RS 23597 (10, 30 and 100 nM) inhibited the response to 5-HT. In addition, 30 and 100 nM RS 23597 reduced the 5-HT response maximum by 30 and 50%, respectively. The pKB value calculated at 10 nM was 8.0. 4. Thus, in the human isolated detrusor muscle, the 5-HT4 receptors mediating facilitation of cholinergic neuromuscular transmission are activated by indoleamines (5-HT, 5-MeOT), substituted benzamide (cisapride, (R,S)-zacopride), benzoate (RS 23597) and benzimidazolone (BIMU 8) derivatives. The activities (in terms of both potency and efficacy) of most agonists, as well as the affinity estimates of the antagonists GR 125487 and DAU 6285, are comparable to those found in other peripheral tissues. Exceptions are RS 23597, which acted either as a partial agonist or as an antagonist of the response to 5-HT1 and 5-MeOT that showed an unusually low potency. The latter findings may be ascribed to differences in the efficiency of receptor coupling mechanisms and/or in the molecular structure (i.e. splice variants) of the 5-HT4 receptor.

Detrusor mast cells in refractory idiopathic instability

The diagnosis of interstitial cystitis (IC) is not usually considered in patients with idiopathic instability. Because histamine provokes detrusor contractions in vitro, we assessed detrusor mast cell counts in 29 females with refractory instability. Raised mast cell counts (greater than 28/mm2 of detrusor muscle, consistent with a histological diagnosis of IC) were found in 29% of such cases. Thus cystoscopy and bladder biopsy should be considered in patients with idiopathic instability which fails to respond to anticholinergic drugs, as alternative therapy may be useful. Patients with refractory instability and normal detrusor mast cell counts often gave a history of prolonged childhood nocturnal enuresis (55% of cases); in contrast, patients with intractable instability and abnormally high mast cell counts seldom gave such a history (12%). These trends may give some insight into the aetiology of idiopathic instability--"congenital" or acquired?

Further studies on the motor response of the human isolated urinary bladder to tachykinins, capsaicin and electrical field stimulation

1. Muscle strips from the dome of the human urinary bladder responded to field stimulation with contractions which were atropine- (3 microM) and tetrodotoxin- (1 microM) sensitive. These contractions were sensitive to omega conotoxin (CTX, 0.1 microM). The atropine- and tetrodotoxin-resistant contractions produced by field stimulation were totally unaffected by CTX. 2. DMPP (30-100 microM), a nicotinic agonist, produced transient bladder contractions which were hexamethonium- and atropine-sensitive. 3. Tachykinins produced a contraction of the human bladder. Among several synthetic tachykinin analogs only those having activity at the NK-2 receptor produced a consistent contractile response. 4. Either capsaicin (1 microM) or calcitonin gene-related peptide (10 nM-0.1 microM) had no motor effect. At 10 microM, capsaicin exerted a depressant effect on nerve-mediated contractions but this effect did not exhibit desensitization. 5. These findings provide evidence that NK-2 receptors are the main if not the sole mediators of the contractile response of the muscle from the dome of the human isolated bladder to tachykinins. 6. No evidence was found for a tachykininergic component in the excitatory response to field stimulation nor for motor responses mediated by capsaicin-sensitive nerves. 7. CTX-sensitive calcium channels are probably present on cholinergic nerve terminals in the human bladder muscle.

The use of endoscopic detrusor muscle biopsies for in vitro muscle strip studies

A technique is described for performing in vitro muscle strip studies using samples of detrusor muscle taken by means of endoscopic biopsy forceps. This study of pig bladder muscle showed that the nerve mediated and drug induced responses of the muscle showed that the nerve mediated and drug induced responses of the muscle biopsies were similar to those produced by traditionally dissected muscle strips. The importance of continued access to human material for pharmacological studies is discussed.

Acetylcholine mediation of the contractile response to histamine in human bladder detrusor muscle

In Krebs solution, histamine evokes in human bladder detrusor muscle strips a dose-dependent contractile response which consists of two pharmacologically distinct responses: a high-sensitivity response evoked at 0.4-2 microM histamine, which is potentiated by neostigmine (0.1 microM) or blocked by atropine (0.1 microM) or ranitidine (1 microM); a low-sensitivity response evoked at 4-40 microM histamine and blocked by dimethindene or diphenhydramine. These findings suggest that the contractile response to low doses of histamine is mediated by acetylcholine released from a site proximal to the muscle. This effect of histamine seems to be mediated by a site which is insensitive to the H1 antagonists dimethindene and diphenhydramine but blocked by the H2 antagonist ranitidine.

Influence of serotonin on lower urinary tract smooth muscle in vitro

The influence of serotonin (5-hydroxytryptamine) on human detrusor and on pig detrusor, trigone, bladder neck and urethral smooth muscle was explored in a series of in vitro experiments. Serotonin evoked a dose-dependent and reversible contraction of the detrusor. The reverse response was triggered in trigone, bladder neck and urethral smooth muscle--a dose-dependent and reversible relaxation. The maximum amplitude of this relaxation was 85 +/- 15% of the relaxation produced by electrical nerve stimulation. The effect of serotonin was unaltered by blockade of ganglia, alpha- and beta-adrenergic receptors, cholinergic receptors and prostaglandin synthesis. The serotonin antagonists ketanserin, methysergide and cyproheptadine partly inhibited the effect of serotonin. The antagonism differed in potency on strips of different origin. The antagonists were ineffective or minimally effective in blocking responses to nerve stimulation. The effect of serotonin was probably mediated by specific serotonin receptors different from the serotonin-S2-receptors predominating in vascular smooth muscle. Serotonin is a potential neurotransmitter in lower urinary tract smooth muscle, but its importance in micturition physiology and pathophysiology is unknown.

Urinary function during epidural analgesia with methadone and morphine in post-cesarean section patients

Urinary function was assessed in 120 women after cesarean section under epidural anesthesia. Postoperative analgesia was obtained by means of epidurally administered methadone (40 patients) or morphine (40 patients). In the remaining 40 women, no narcotic drugs were given and postoperative pain was treated with intramuscular or oral non-opiate analgesics and sedatives. Both methadone and morphine provided potent postoperative pain relief. Following epidural methadone, mean urine volumes of the first two postoperative voidings were increased (543 +/- 38 ml and 571 +/- 31 ml) as compared with those after epidural morphine (219 +/- 25 ml and 218 +/- 18 ml) and with those of patients receiving non-opiate analgesics (319 +/- 28 ml and 414 +/- 30 ml). The mean time interval between the end of surgery and first voiding following methadone analgesia was shorter (336 +/- 27 min) than after morphine (582 +/- 18 min) or after non-opiate (448 +/- 28 min) analgesic drugs. Difficulty in micturition and the need for bladder catheterization were also decreased in the group with epidural methadone (2.5%) in comparison with the groups receiving morphine (57.5%) or non-opiate analgesic medicaments (12.5%). The use of epidural methadone for postoperative pain relief is advocated, both in view of its analgesic potency and of the low incidence of urinary disturbances.

Atropine blockade of nerve-mediated stimulation of the human detrusor

The effect of atropine on the isometric contractile response of isolated human detrusor muscle strips to electrical field stimulation has been studied. A 94.1% reduction in the response in the presence of tetrodotoxin demonstrated the neuronal nature of the stimulus. Atropine caused a 92.7% inhibition of the response. It was concluded that the nerve-mediated stimulus in human detrusor is cholinergic in nature and that "atropine resistance" does not occur in man.

Conservative Treatment of Female Stress Incontinence with Imipramine

The results of a clinical study of conservative treatment of women with stress incontinence are presented. A daily dose of 75 mg. imipramine hydrochloride was given for 4 weeks. Special attention was paid to the effects of imipramine on the functional urethral length and maximum urethral closure pressure. A total of 21 women (71 per cent) stated that they were continent after treatment with imipramine, while 9 (29 per cent) did not improve and treatment was stopped. According to our results, imipramine extended the functional urethral length and made it independent of stress factors in women who were continent after treatment with imipramine. In patients with persistent incontinence the functional urethral length was extended significantly but was shortened with stress despite imipramine therapy. We believe that imipramine could be an alternative treatment in selected cases with stress incontinence.

A comparison of spontaneous and nerve-mediated activity in bladder muscle from man, pig and rabbit

Spontaneous activity in bladder muscle strips from man, pig and rabbit has been compared using an in vitro superfusion technique. Field stimulation was used to study nerve-mediated activity. Bladder muscle strips from all areas of the rabbit bladder displayed rhythmic spontaneous activity. Spontaneous activity was regularly present in strips from the trigone region in man and pig, but was present in only 18 and 19% respectively of strips from the dome of the bladder. Strength-duration curves in the presence of tetrodotoxin (10(-7) g/ml) were constructed. The 'chronaxie' of the muscle was found to be considerably shorter than that of other smooth muscles, ranging from 6.1 ms in the rabbit to 12.9 ms in man. Frequency-response curves were constructed using trains of stimuli. The responses were not antagonized by hexamethonium (10(-4) M), but were markedly inhibited by tetrodotoxin (10(-7) g/ml), indicating that the responses were mediated by excitation of post-ganglionic nerves. Physostigmine (10(-7)-5 X 10(-6) M) produced a dose-related increase in the contractile response to field stimulation in all three species. Atropine (10(-8)-10(-6) M) produced an inhibition of the contractile response, but the maximum degree of inhibition differed considerably between the species. In the rabbit, 58% of the control response was attained, whilst in the pig this was only 22%. Atropine completely abolished nerve-mediated contractions in human bladder muscle. Phentolmaine (10(-7)-2.5 X 10(-7) M) had no significant effect on the frequency-response curve in any of the three species, and did not depress the atropine-resistant component in rabbit and pig. It is concluded that nerve-mediated activity in human bladder muscle is exclusively cholinergic, in contrast to most other mammals studied in which there is a significant non-cholinergic component. The finding of a shorter chronaxie in bladder muscle than in other smooth muscles suggests important differences in its physiological properties that merit further investigation.

New approach to study of voiding cycle in cat. Preliminary report on pharmacologic studies

The effect of autonomic active agents were studied on 23 anesthetized cats. The parameters recorded were circular and longitudinal urethral muscles, and bladder muscle contractions and relaxation as well as intravesical pressure during voiding cycles. Cholinergic stimulant (bethanechol) and blockage (atropine) excited or inhibited the bladder muscle and minimally affected the urethra. Alpha-adrenergic stimulant (norepinephrine) in nonatropinized animals produced mild stimulation on the bladder, and longitudinal-circular urethral muscle synergia appeared to be inadequate. In atropinized animals norepinephrine produced the reverse effect, causing marked inhibition. Alpha blockade (phentolamine) disinhibited the receptors mainly in the bladder and improved the urethral synergia. Beta stimulant (isoproterenol) inhibited the bladder and urethral muscles, and beta blockade (propranolol) stimulated the bladder and urethral muscles.

Response of the urethral smooth muscles to pharmacological agents. I. Cholinergic and adrenergic agonists and antagonists

We studied the effects of cholinergic and adrenergic agents on the 2 muscle layers of the proximal urethra of the cat. Strips were challenged with bethanechol chloride, phenylephrine and isoproterenol. Bethanechol chloride caused contraction of the longitudinally oriented strips; the circularly oriented strips revealed either minimal or no response to the same doses. The difference between the response of the 2 layers was highly significant (p less than 0.001). Phenylephrine stimulated both layers with a nonsignificant difference. Isoproterenol caused relaxation of both layers with a significant action on the circularly oriented fibers (p less than 0.05). It could be concluded that the cholinergic effect which is predominant on the longitudinal fibers is important for voiding by shortening the proximal urethra. alpha-adrenergic innervation of the bladder neck has a function during ejaculation: closure of the bladder outlet by the circular fibers. beta-adrenergic agonists decrease the urethral pressure probably by relaxing both layers with a dominant effect on the circular layer.

Regulation of bladder and colon--rectum in patients with spinal lesions

Parasympathetic cholinergic stimulation is excitatory for bladder and colon--rectum, normal as well as uninhibited. This is documented by pharmacological and neuroanatomical studies in man. The bladder and the left half of colon and rectum have motor supply in common as demonstrated by surgical intervention on sacral nerves. More detailed studies can be performed by electrical stimulation of sacral roots or rootlets. Sympathectomy may cause alteration of voiding pattern, but often only temporarily, and generally with no alteration of defecation habits. The sympathetic innervation is sparse in the human bladder, but alpha- and beta-adrenergic receptors have been demonstrated. The alpha-adrenergic blocking agent thymoxamine is able to cause a shift in the cystometrogram to the right, and to relax the spastic pelvic sphincters by i.v. administration. Like other alpha-adrenergic blocking agents, it can relax the proximal part of the urethra. The effect of other stimulating and blocking adrenergic compounds are reported, but further studies are needed. No simultaneous reactions are generally recorded in the uninhibited bladder and rectum, and no correlation was found between the hyperactivity of the uninhibited neurogenic bladder and colon.

An in vitro physiological study of normal and unstable human detrusor muscle

A systematic in vitro physiological study of isolated human detrusor muscle strips is reported. Detrusor strips were obtained at operation. Pre-operative urodynamic studies enabled specimens to be classified as normal or unstable. Comparisons were made between responses of normal and unstable detrusor strips. The results provide evidence of a previously undescribed feedback-loop operating via pre-synaptic alpha-adrenoceptors which controls detrusor contractility. Further evidence is provided suggesting that an imbalance in this system is present in unstable detrusor muscle.

Adrenergic response of bladder muscle in prostatic obstruction. Its relation to detrusor instability

In vitro isometric studies of bladder dome muscle taken at operation from 47 patients with benign prostatic obstruction, revealed an alpha-adrenergic response instead of the normal beta response in 23 per cent. The relationship between this finding and the presence of irritative symptoms and an unstable detrusor is examined. This finding may explain the beneficial effect of alpha-blockers on these symptoms in many patients with prostatic obstruction.

Influence of the adrenergic nervous system on the lower urinary tract and its clinical implications

The morphology of the adrenergic nervous systems as well as adrenoceptor functions of the human lower urinary tract are outlined and compared to some animal studies. Special emphasis is given to the altered adrenergic innervation and adrenoceptor function after parasympathetic decentralization. Pharmacological treatment affecting adrenoceptors is described in different disturbances of lower urinary tract function and some evidence for adrenergic mechanisms working in intravaginal electrical stimulation is presented. The importance of the sympathetic nervous system for the normal function of the human lower urinary tract is still unclear. Nevertheless, clinical data obtained by treatment with agents influencing this system indicate that the contractory alpha-adrenoceptors of the human urethra can be stimulated or blocked pharmacologically producing significant changes in intraurethral pressure. On the other hand, the relaxatory effect on the human detrusor obtained by stimulation of the beta-adrenoceptors seems to be negligible.

Neuromuscular transmission in the corpus-fundus of the urinary bladder. An in vitro study in the cat

In muscle strips from the corpus-fundus of the cat bladder the intramural nervous system was activated by field stimulation. The resulting muscle contraction could not be inhibited by atropine, phentolamine or quinidine. These drugs enhanced the response. Tetrodotoxin, methysergide, cyproheptadine and indomethacin blocked the field-stimulation response in a dose dependent manner. The interpretation of these results with references to transmission at the neuromuscular junction of the bladder is discussed.

Smooth muscle physiology and effect of bladder and urethra muscle length/tension on response to stimulation. Part I. Review

With particular reference to the lower urinary tract, a review of basic anatomy and physiology of smooth muscle is presented. The relationship as altered by electrica and pharmacologic stimulation is discussed.

Augmentation of bladder contractility after beta-adrenergic blockade in spinal cord injured patients

Six spinal cord injured patients were evaluated with cystometry, bladder electromyography, and external urethal spincter pressure profiles before and after propranolol hydrochloride administration. Bladder contractility was significantly augmented, and therefore was associated with decreased beta-sympathetic bladder stimulation. The results of these clinical neurophysiological investigations suggest inhibitory influences upon the smooth muscle of the human urinary bladder via beta-sympathetic receptors.

Effect of the alpha-adrenergic blocking agent thymoxamine on the neurogenic bladder and urethra

The effect of the alpha-adrenergic blocking agent thymoxamine by intravenous administration was studied in 25 patients with spastic paraplegia and uninhibited neurogenic bladder. By cystometry a shift to the right of the first desire to void, the threshold of the first uninhibited contraction and a reduction of the pressures of the uninhibited contractions was found, but the bladder capacity was unchanged. The urethral pressure profile studied in 10 patients showed reduction in most and the peak value in all the patients. EMG from the external urethral sphincter in five patients showed damping of anal reflexes in all cases and in basic activity and cough reflexes when appropriate for studies. The site of action on the bladder is most likely adrenergic receptors in the bladder and the unchanged bladder capacity may be related to a too-short duration of the effect of thymoxamine. The effect on the spastic striated pelvic sphincters may be central, whereas the effect on the smooth muscle may be peripheral. Feedback from the drug relaxed proximal part of the urethra to the bladder might also be of importance.

Uropharmacology: X. Central nervous system stimulants and depressants

Several drugs that are utilized primarily for their effects on the central nervous system also affect lower urinary tract function. Most of these effects are produced by the action of these drugs on adrenergic and cholinergic receptors or by direct action of lower urinary tract musculature. Central nervous system stimulants and depressants which are known to affect the storage or evacuation role of the lower urinary tract are discussed.

Management of neurogenic bladder in infancy and childhood

Sixty-two patients, age twelve years and under, were treated for incontinence due to neurogenic bladder secondary to spina bifida (58) or trauma (4) with a follow-up period of three to thirty-two months (mean, ten months). In early life, patients were managed with the Credé maneuver (18 patients). Older children were managed with intermittent clean catheterization (44 patients) with or without pharmacologic agents. Continence was achieved with intermittent clean catheterization in 77 per cent, thus enabling these children to be more acceptable to their peers and in many cases attend schools from which they had previously been excluded because of urinary incontinence. With the Credé maneuver, renal deterioration was noted in 11 per cent on follow-up IVP, and in 2 per cent of the patients on intermittent clean catheterization. Recurrent asymptomatic bacteriuria occurred in 33 per cent of those with the Credé maneuver and in 55 per cent of the patients using intermittent clean catheterization. The use of antibiotic bladder irrigations reduced this incidence to 5 per cent. All patients with renal deterioration except one responded to intermittent clean catheterization; this patient was treated with cutaneous vesicostomy. Urodynamic assessment was performed in 15 patients, and this diagnostic tool assisted in the therapeutic management of these children.

Insulin production by pancreatic islets of obese-hyperglycemic mice cultured for one week in different glucose concentrations

Culture of pancreatic islets isolated from obese-hyperglycemic mice (gene symbol ob) for one week in media containing widely different concentrations of glucose (3.3, 5.6 or 16.7 mM) was found to markedly influence the functional behaviour of the islet B-cells. Thus, the insulin content of islets cultured at 3.3 or 16.7 mM glucose (subphysiological or supraphysiological glucose concentrations respectively) was markedly reduced. Islets cultured in 5.6 or 16.7 mM glucose displayed a normal insulin secretory response when stimulated with glucose, whereas islets cultured in a subnormal glucose concentration (3.3 mM) showed a reduced insulin response to glucose stimulation in batch type incubations and also lacked a second phase of insulin secretion in islet perifusion experiments. The rate of insulin biosynthesis of non-cultured ob/ob islets was higher than that of islets from their lean siblings but culture for one week in 3.3 mM glucose induced a pronounced impairment of the insulin biosynthesis in islets of obese as well as lean mice. The present data indicate that the hyperfunction of the islets of the ob/ob mouse at least in part is a reversible phenomenon, suggesting that inherent properties of islet B-cells do not act as "primary" factors in the development of the obese-hyperglycemic syndrome.

Uropharmacology: VIII. Sympathomimetic agents

Sympathomimetic drugs stimulate the receptors of the sympathetic nervous system. Although the bladder possesses sympathetic receptors, sympathomimetic drugs, in general, have little effect on bladder function. Their most useful clinical applications on the urinary tract are to increase or decrease bladder resistance.

Uropharmacology: VII. Ganglionic stimulating and blocking agents

A classification of the various ganglionic stimulants and blockers is presented, and their pharmacologic effects on the urinary bladder and urethra are discussed. Ganglionic stimulating drugs are of considerable interest in investigational work but are not presently used therapeutically. Ganglionic blockers include hexamethonium, tetraethylammonium, mecamylamine emepronium, pentolinium, chlorisondamine, and pemipidine. Of the numerous ganglionic blocking drugs that have appeared on the therapeutic scene, only mecamylamine, pentolinium, and trimethaphan are currently official.

The effects of norephedrine and bethanechol on the human urethral closure pressure profile

In twelve women with urinary stress incontinence simultaneous measurements were made of the intravesical and intra-urethral pressures, including the urethral closure pressure profile (UCPP), before and after oral administration of norephedrine or subcutaneous injection of bethanechol. The investigations were carried out at various bladder volumes in the supine position and at bladder volume 300 ml in erect position. Irrespective of bladder volume or body position, norephedrine caused a statistically significant rise in maximum urethral pressure (MUP) and in maximum urethral closure pressure (MUCP). The intravesical pressure was not affected. After intravenous injection of phentolamine, MUP and MUCP fell to levels below the original readings, but here too the intravesical pressure was unaffected. Injection of bethanechol was followed by significant increase in the intravesical pressure, irrespective of bladder volume or body position. There were no consistent changes in the intra-urethral pressure. As a consequence of the rise in intravesical pressure, however, the MUCP fell slightly. The results of the study suggest that orally administered norephedrine causes an increase in the MUCP in women with stress incontinence of urine, an increase that may prove therapeutically useful. Bethanechol, in doses that significantly increased intravesical pressure, did not alter the intra-urethral pressure.

Uropharmacology: part VI. Parasympathetic depressants

A discussion of the various parasympathetic depressants is presented. Belladonna alkaloids include atropine, the prototype, and scopolamine. Synthetic drugs include quaternary ammonium compounds with antimuscarinic activity such as methantheline, propantheline, and other drugs such as isopropamide, pipenzolate methylbromide, and diphemanil methylsulfate. A miscellaneous class of drugs such as hemicholinium, valethamate, and oxybutynin chloride also possesses parasympathetic depressant activity. The pharmacologic properties and clinical usage of these drugs are discussed.