Urinary Bladder Body Research Articles

Creation of a Continent Urinary Bladder Reservoir Vascularized by Omentum as a Possible Surgical Option for Canine Trigonal/Urethral Urothelial Carcinoma

Surgical procedures that maintain continence with minimal complication following resection of trigono-urethral urothelial carcinoma (UC) are limited in canines; therefore, palliative options are often pursued. A feasible tumor resection option may improve disease control and survival. The study’s objective was to evaluate a continent urine reservoir created from the urinary bladder body and vascularized solely by omentum. We hypothesized that a viable urine reservoir could be created, and staged omentalization would provide improved vascularity. Nine normal female Beagles were randomized to one of three groups. Group A urinary bladders were transected cranial to the ureteral papillae to create a closed bladder vesicle which was concomitantly omentalized. Group B underwent omentalization two weeks prior to vesicle creation. Based on Group A and B results, Group C underwent neoureterocystostomy and omentalization followed by neoreservoir formation and tube cystostomy 2 weeks later. Serial ultrasounds and histopathology confirmed adequate omental neovascularization in Groups B and C with continent Group C neoreservoirs maintained for 2 months. Some pylectasia and ureteral dilation was documented in all Group C dogs at variable timepoints. Progressive hydroureteronephrosis developed in 2/6 kidneys. Transient azotemia was noted in only 1 Group C dog, although all developed treatable urinary tract infections. The sample size is limited, and the efficacy of this technique in providing disease control for UC is unknown. However, this novel option could allow for primary UC resection while providing continence and limiting complications. Postoperative local or systemic adjuvant therapy, ultrasonographic neoreservoir monitoring, and BRAF analysis would be indicated.

Biodistribution and post-therapy dosimetric analysis of [177Lu]Lu-DOTAZOL in patients with osteoblastic metastases: first results

BackgroundPreclinical biodistribution and dosimetric analysis of [177Lu]Lu-DOTAZOL suggest the bisphosphonate zoledronate as a promising new radiopharmaceutical for therapy of bone metastases. We evaluated biodistribution and normal organ absorbed doses resulting from therapeutic doses of [177Lu]Lu-DOTAZOL in patients with metastatic skeletal disease.MethodFour patients with metastatic skeletal disease (age range, 64–83 years) secondary to metastatic castration-resistant prostate carcinoma or bronchial carcinoma were treated with a mean dose of 5968 ± 64 MBq (161.3 mCi) of [177Lu]Lu-DOTAZOL. Biodistribution was assessed with serial planar whole body scintigraphy at 20 min and 3, 24, and 167 h post injection (p.i.) and blood samples at 20 min and 3, 8, 24, and 167 h p.i. Percent of injected activity in the blood, kidneys, urinary bladder, skeleton, and whole body was determined. Bone marrow self-dose was determined by an indirect blood-based method. Urinary bladder wall residence time was calculated using Cloutier’s dynamic urinary bladder model with a 4-h voiding interval. OLINDA/EXM version 2.0 (Hermes Medical Solutions, Stockholm, Sweden) software was used to determine residence times in source organs by applying biexponential curve fitting and to calculate organ absorbed dose.ResultsQualitative biodistribution analysis revealed early and high uptake of [177Lu]Lu-DOTAZOL in the kidneys with fast clearance showing minimal activity by 24 h p.i. Activity in the skeleton increased gradually over time. Mean residence times were found to be highest in the skeleton followed by the kidneys. Highest mean organ absorbed dose was 3.33 mSv/MBq for osteogenic cells followed by kidneys (0.490 mSv/MBq), red marrow (0.461 mSv/MBq), and urinary bladder wall (0.322 mSv/MBq). The biodistribution and normal organ absorbed doses of [177Lu]Lu-DOTAZOL are consistent with preclinical data.Conclusion[177Lu]Lu-DOTAZOL shows maximum absorbed doses in bone and low kidney doses, making it a promising agent for radionuclide therapy of bone metastasis. Further studies are warranted to evaluate the efficacy and safety of radionuclide therapy with [177Lu]Lu-DOTAZOL in the clinical setting.

Differences between young and aged rats in voiding frequency and detrusor muscle serotonergic contraction.

The involvement of serotonin (5-HT) in increased lower urinary tract symptoms in aging is unclear. We sought to compare voiding function and 5-HT induced detrusor contraction between young and aged rats. This study used young (2- to 3-month-old) and aged (26- to 30-month-old) male Fischer 344 rats. 1. Rats were housed in individual metabolic cages, and then the total volume of urination, volume per micturition, voiding frequency, and voiding interval were analyzed. 2. Using urinary bladder body strips, developed tension was recorded after cumulative addition of 5-HT (1-100 nM) in the absence or presence of tetrodotoxin (1 μM), and in the presence of tetrodotoxin with ketanserin (0.3-3 μM) or naftopidil (1 and 3 μM). We examined the effects of atropine, ketanserin, and naftopidil on electrical field stimulation (EFS)-induced contraction. 1. Compared to young rats, aged rats exhibited decreased voiding frequency and increased volume per micturition, but total volume of urination (normalized to body weight) did not differ. Moreover, voiding interval was significantly prolonged in aged rats during the active period. 2. In the presence of tetrodotoxin, pEC50 of 5-HT were significantly lower in aged rats than in young rats (P < 0.01), but the maximal response to 5-HT was not altered in the aged bladder. Ketanserin inhibited 5-HT-induced contraction in both groups, while suppression by naftopidil was relatively limited, especially in aged rats. EFS induced neurogenic contraction in a frequency-dependent manner. Atropine-resistant contraction was not inhibited by naftopidil, but was potentiated by ketanserin. Urination intervals were extended in aged rats, indicating that urination rhythm changed. In the senescent rat bladder, 5-HT induced detrusor contraction, but the effect of 5-HT and the naftopidil-sensitive contractile force were weaker than those in young rats. Additionally, 5-HT did not contribute to the increase in atropine-resistant EFS-induced contractions in aged rats.

First in-human radiation dosimetry of the gastrin-releasing peptide (GRP) receptor antagonist 68Ga-NODAGA-MJ9

BackgroundGastrin-releasing peptide receptor antagonists have promise in theranostics of several highly incident tumours, including prostate and breast. This study presents the first human dosimetry of 68Ga-NODAGA-MJ9 in the first five consecutive patients with recurrent prostate cancer included in a dual-tracer positron emission tomography (PET) protocol. Five male patients with biochemical relapse of prostate adenocarcinoma underwent four whole-body time-of-flight PET/CT scans within 2 h after tracer injection. To be used as input in OLINDA/EXM 2.0, time-integrated activity coefficients were derived from manually drawn regions of interest over the following body regions: brain, thyroid, lungs, heart, liver, gallbladder, spleen, stomach, kidneys, adrenals, red marrow, pancreas, intestines, urinary bladder and whole body. Organ absorbed doses and effective dose (ED) were calculated with OLINDA/EXM 2.0 using the NURBS voxelized phantoms adjusted to the ICRP-89 organ masses and ICRP103 tissue-weighting factors. Additional absorbed dose estimations were performed with OLINDA/EXM 1.1 to be comparable with similar previous publications.ResultsThe body regions receiving the highest absorbed doses were the pancreas, the urinary bladder wall, the small intestine and the kidneys (260, 69.8, 38.8 and 34.8 μGy/MBq respectively). The ED considering a 30-min urinary voiding cycle was 17.6 μSv/MBq in male patients. The increment of voiding time interval produced a significant increase of absorbed doses in bladder, prostate and testes, as well as an increase of ED. ED also increased if calculated with OLINDA/EXM 1.1. These results have been discussed in view of similar publications on bombesin analogues or on other commonly used theranostic peptides.ConclusionsThe pancreas is the most irradiated organ after the injection of 68Ga-NODAGA-MJ9, followed by the urinary bladder wall, the small intestine and the kidneys. ED is in the same range of other common 68Ga-labelled peptides. Differences with similarly published studies on bombesin analogues exist, and are mainly dependent on the methodology used for absorbed dose calculations.Trial registrationClinicaltrial.Gov identifier: NCT02111954, posted on 11/042014.

Selective changes in the &lt;i&gt;α&lt;/i&gt;-adrenoceptor-mediated contraction in the senescent rat urinary bladder

The urinary bladder is innervated and functionally regulated by the autonomic nervous system. In order to elucidate the mechanism of functional changes in aged rat urinary bladder, we studied the influence of senescence on, 1) the α-adrenergic contractile response to phenylephrine in the urinary bladder body and trigone, 2) the muscarinic contractile response to carbachol in the body and trigone. The binding characteristics of [3H]quinuclidinyl benzilate (QNB) to muscarinic cholinoceptors were compared in young and aged bladder. Bladders from young (2 - 3 month-old) and aged (27 month-old) male Fischer 344 rats were isolated, cut into strips and mounted in the organ bath, then the developed tension was recorded. Histologically, the aged bladder did not show pathologic changes such as inflammation and hypertrophy. Carbachol-induced contraction in aged rat bladder was identical to that obtained in young rat. In the receptor binding assay, [3H]QNB maximal binding capacity and Kd value were not significantly changed in aged bladder. In contrast, a selective α-adrenergic agonist phenylephrine, elicited greater contractions both in the aged body and trigone than those in young rats. The augmentation of α-adrenoceptor-mediated contractions in aged bladder may induce urinary dysfunction such as voiding difficulty.

Antioxidant Levels in the Pig Urinary Bladder: Distribution within the Bladder Wall and in the Urothelium Derived from Different Bladder Regions

This study was designed to determine the antioxidant levels in the urinary bladder wall layers as well as urothelium derived from different bladder regions. Samples of the urothelium, lamina propria, muscularis, and serosa were prepared from the pig's urinary bladder body, while samples used for regional mapping of the urothelium were prepared from trigone, ventral and dorsal middle bladder body, and apex region. Activities of superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase were determined. Concentrations of ascorbic acid and glutathione were also measured. Antioxidant activities, i.e. concentrations of superoxide dismutase, glutathione peroxidase, glutathione reductase and glutathione, were shown to be highest in the urothelium and progressively lower towards the serosa. Regional mapping of the urothelium singled out apex as the region with the lowest antioxidant activities, i.e. concentrations of glutathione peroxidase, ascorbic acid, and glutathione. The fact that antioxidants are concentrated in the urothelium implies that urothelium functions as a barrier against reactive species. The urothelium derived from the apex is the region with the lowest antioxidant levels and is therefore probably the region most liable to development of oxidative damage.

Heterogeneity of Morphological and Functional Changes in Various Compartments of Rat Urinary Bladder in Infravesical Obstruction of the Urinary Tract

Infravesical obstruction of the lower urinary tract was simulated in rats by dosed constriction of the prevesical portion of the urethra. The functional and morphological changes in various urinary bladder compartments were evaluated after 1 week and 3 months. The development of compensatory hypertrophy of the detrusor was associated with an increase in the number of hypertrophic, atrophic, and young leiomyocyte forms and their transformation into myofibroblasts, with the formation of connective tissue laminae between myofibril bundles mainly in the zone of urinary urinary bladder neck. Specific contractility of the detrusor strips decreased with increasing their tone, which was most pronounced in the neck zone. The relaxing effect of norepinephrine was significantly lower after 3 months of obstruction and virtually disappeared in the zone of the urinary bladder body and neck. Blockade of a-adrenoceptors after adrenostimulation with norepinephrine stimulated contractions of the hypertrophic detrusor against the background of reduced tone of the urinary bladder neck, in contrast to intact urinary bladder where this treatment reduced contractions.

Pharmacological characterization of beta-adrenoceptors mediating relaxation of the rat urinary bladder in vitro.

1. Isoproterenol relaxed KCl-precontracted rat bladder strips with a pD2 of 7.21 leaving a residual contractile response of 3.2% after 30 microM. The selective beta1-agonist, T-0509 (pD2 : 6.24, 10.1% residual contraction after 100 microM), beta2-agonist, terbutaline (pD2 : 5.43, 13.7% residual contraction after 100 microM), and beta3-agonists, BRL 37344A (pD2 : 6.60, 17.3% residual contraction after 100 microM), and SR 58611A (pD2 : 5.15, 34.0% residual contraction after 100 microM), also relaxed bladder strips. 2. The relaxant response to isoproterenol was weakly but significantly antagonized by 1 microM propranolol which produced a 3 fold shift of the concentration-response curve to the right, and significantly antagonized by the beta1-selective antagonist, metoprolol (10 microM, 3 fold shift), and the beta2-selective antagonist, butoxamine (100 microM, 6 fold shift). A combination of 10 microM metoprolol and 100 microM butoxamine caused a 15 fold shift of the concentration-response curve for isoproterenol to the right. Incubation with the beta3-antagonist, SR 59230A (1 microM), caused a 6 fold shift of the concentration response curve for isoproterenol to the right. 3. The non-conventional partial agonist, CGP 12177A, weakly relaxed KCl-precontracted bladder strips (pD2 : 3.31, 51.3% residual contraction after 300 microM); the relaxation was resistant to blockade by 1 or 10 microM propranolol. 4. In the presence of 200 microM propranolol, CGP 12177A (20 microM) or SR 59230A (10 microM) antagonized surmountably the relaxant effects of BRL 37344A. 5. The data suggest that rat urinary bladder body contains beta1, beta2, and beta3-adrenoceptors, all of which mediate relaxation.

Responsiveness of smooth muscle in the lower urinary tract of rabbits to various agonists

1. 1. We compared the responsiveness of smooth muscle in the lower urinary tract and prostate from rabbits to the agonists noradrenaline, phenylephrine, clonidine, acetylcholine, prostaglandin F 2α, and histamine. 2. 2. These agonists contracted smooth muscle in the lower urinary tract and prostate. In terms of maximal developed tension, contractile responses to the agonists were produced in the following order of potency: acetylcholine>prostaglandin F 2α>histamine⩾phenylephrine⩾noradrenaline>clonidine in the urinary bladder body; acetylcholine=noradrenaline=phenylephrine>prostaglandin F 2α>histamine⩾clonidine in the urinary bladder base; noradrenaline⩾phenylephrine⩾clonidine>acetylcholine>prostaglandin F 2α⩾histamine in the urethra; and noradrenaline⩾phenylephrine>histamine= acetylcholine=clonidine=prostaglandin F 2α in the prostate. 3. 3. These results suggest that considerable responsiveness variation occurs in the lower urinary tract and prostate and support the idea that the urinary bladder body is primarily governed by cholinergic mechanisms (parasympathetic nerves), whereas the urethra and prostate are regulated by α 1-adrenergic mechanisms (sympathetic nerves) and the bladder base by both.

Influence of strip size and location on contractile responses of rat urinary bladder body strips

1. 1. We investigated the influence of strip length and dorsal or ventral location of rat urinary bladder strips on contractile responsiveness. 2. 2. No differences occurred in the contractile responses of 0.5, 1.0 and 2.0 cm strips to field stimulation, carbachol, ATP, substance P or to KCl when the data were expressed as either absolute tension or as tension per cross-sectional area. However, correction for strip mass resulted in significant decreases in the contractile responses of the 2.0-cm strips compared with the 0.5-cm strips. 3. 3. No differences occurred in length-tension curves for ventral and dorsal bladder strips, even though the strips from the dorsal surface appeared thinner than those from the ventral surface. 4. 4. Strips from the ventral surface exhibited more variability in response to field stimulation and were less sensitive to atropine pre-treatment than were those from the dorsal surface. They were also less sensitive to the contractile effects of carbachol than dorsal strips. Dorsal and ventral strips were equally responsive to ATP, substance P and KCl. 5. 5. Our data indicate that the contractile responsiveness of rat urinary bladder strips is independent of strip length. Although there are some differences between the cholinergic responsiveness of strips from the ventral and dorsal surfaces of the bladder, the differences are so small that for most studies they will probably have no influence on data interpretation.

Effects of prostaglandins E1, E2 and F2 alpha on contractility and cAMP and cGMP contents in lower urinary tract smooth muscle.

Prostaglandin (PG) E1, E2 and F2 alpha contracted smooth muscle strips from male adult rabbit urinary bladder. Contractile responses to each PG were significantly greater in urinary bladder body than in urinary bladder base. The magnitude of contractile response to each PG was F2 alpha > E2 > E1 in both of the bladder body and the bladder base. These contractions were almost completely eliminated by a calcium entry blocker, verapamil but not by atropine, phentolamine, propranolol or tetrodotoxin. PG E1 and E2 significantly relaxed the male rabbit urethral smooth muscle strips, whereas PG F2 alpha contracted the urethral smooth muscle strips. Cyclic adenosine monophosphate (cAMP) but not cyclic guanosine monophosphate (cGMP) increased significantly after administration of PG E1 or E2 in the urethral muscle strip. These results suggest that the regional differences in the magnitude of contractile responses to PG E1, E2 and F2 alpha between the bladder dome and the base and also suggest the contractile differences of PG E1 and E2 for the urinary bladder and the urethra; contractions for bladder and relaxations for urethra. These results also demonstrate that contractions induced by PG E1, E2 and F2 alpha in urinary bladder smooth muscles and by PG F2 alpha in urethral smooth muscles are mainly mediated by calcium influx and that relaxations induced by PG E1 and E2 in urethral smooth muscles are mediated by cAMP but not by cGMP.

Adrenergic innervation of the urinary bladder body in the cat with special reference to structure of the detrusor muscle: an immunohistochemical study of noradrenaline and its synthesizing enzymes.

The distribution of adrenergic nerves in the body detrusor muscle of the cat urinary bladder was studied by means of the immunohistochemical identification of noradrenaline (NA) and the NA synthesizing enzymes tyrosine hydroxylase, aromatic L-aminoacid decarboxylase and dopamine beta-hydroxylase. We identified the basic structural organization of the detrusor muscle, which had previously been described as lacking discernible layers. In the lateral wall, both outer longitudinal and inner circular muscle bundles were present, the latter extending in both anterior and posterior directions. The posteriorly running bundles came to lie on the outside of the posterior wall where they enabled recognition of inner longitudinal muscle bundles. Those running anteriorly were dispersed to enter the longitudinal bundles in the anterior wall. NA-immunoreactive nerve fibers in the detrusor muscle of the bladder were found to be similar to those immunoreactive for NA synthesizing enzymes in both distribution and density. In the upper and middle bladder body--including the dome (apex)--immunoreactive nerve fibers were always more abundant in the outer part of the detrusor muscle than in the inner part, regardless of the course of muscle bundles. Even in individual muscle bundles running from the inside to the outer surface, the outer part was more richly innervated by immunoreactive fibers than the inner part. In the bladder dome, a moderate number of immunoreactive nerve fibers preferentially innervated the outer part of the muscle layer. In the lower bladder body, these nerve fibers increased in density in the inner part of the detrusor muscle. There was no sexual difference in density or distribution of nerve fibers. NA- and NA synthesizing enzyme-immunoreactive nerve fibers were markedly decreased in number after 6-hydroxydopamine treatment. No dopamine- or phenylethanolamine-N-methyltransferase-immunoreactive nerve fibers were present in the bladder. The findings of this study indicate that the cat bladder musculature includes longitudinal and circular muscle bundles, both of which are extensively innervated by adrenergic nerves, particularly in the outer part of the bladder.

Effect of capsaicin on distribution of binding sites for tachykinins and calcitonin gene-related peptide in rat urinary bladder: A quantitative autoradiographic study

The autoradiographic localization of binding sites for [ 125I]BH-[Sar 9,Met(O 2) 11]SP, [ 125I]NKA, and [ 125I]CGRP was investigated in adjacent sections of urinary bladder body, from adult rats pretreated 14 days before with capsaicin or vehicle. Location of silver grains was assessed both qualitatively and quantitatively using computerized densitometry. Dense labeling of smooth muscle was seen with both [ 125I]BH-[Sar 9,Met(O 2) 11]SP ([ 125I]BHSar-SP) and [ 125I]NKA; in addition, [ 125I]BHSar-SP labeled submucosal blood vessels. For these radioligands, no differences were apparent between sections from capsaicin- and vehicle-pretreated rats. Specific binding of [ 125I]CGRP was observed over the epithelium and weakly over submucosal arterioles, but not over smooth muscle. The density of [ 125I]CGRP binding sites on the epithelium, but not blood vessels, was increased ( p < 0.05) by 22% after chronic capsaicin pretreatment, suggesting receptor upregulation. This study demonstrates that although all three peptides are colocalized in primary afferent sensory fibers in rat urinary bladder, the receptors for these neuropeptides are located on different cell types and may be subject to different neural influences.

Effect of Tetrodotoxin on the Phasic and Tonic Responses of Isolated Rabbit Urinary Bladder Smooth Muscle to Field Stimulation

The response of the rabbit urinary bladder to field stimulation (80 volts, 2–32Hz, 1 msec duration) is biphasic, consisting of an initial phasic contraction mediated by cholinergic and purinergic neurotransmitters, followed by a prolonged tonic contraction which is solely cholinergic. Obstructive hypertrophy of the bladder induces a variety of contractile alterations including a significantly greater reduction in the tonic component of the contractile response as compared to the phasic component. This results in a severe dysfunction in the ability of the bladder to empty. One possibility is that the inability of the bladder to maintain tension and empty efficiently may be related to a degeneration of nerves innervating the bladder smooth muscle.In addition to the well documented neuropathy, the bladder undergoes hypertrophy ± hyperplasia of both smooth muscle and interstitial cellular elements, alterations in the metabolism of substrates, alterations in the synthesis of structural and smooth muscle proteins, and alterations in the deposition of collagen. The purpose of this study was to 1) to create a specific neuropathy in the absence of the additional structural, smooth muscle, and metabolic changes that are induced by partial outlet obstruction; and 2) determine if the contractile dysfunctions induced by the neuropathy have properties similar to the contractile dysfunctions induced by outlet obstruction.In the present study, a progressive “smooth muscle neuropathy” was induced in isolated strips of male rabbit urinary bladder smooth muscle by incubating isolated strips of urinary bladder body in the presence of increasing concentrations of tetrodotoxin (15–1500nM). In these studies, we determined the effect of increasing concentrations of tetrodotoxin (TTX) on the response to field stimulation utilizing 2Hz and 32Hz, at 80V and 1ms duration. The effects of TTX on maximum rate of contraction, peak contraction and tonic contraction were monitored. In addition, the effects of atropine (cholinergic muscarinic blockage) and ATP-desensitization (purinergic inhibition) on the effects of TTX were also determined. The results can be summarized as follows: 1) Both atropine and ATP desensitization individually inhibited significantly the peak response to field stimulation. 2) Atropine abolished the tonic response. 3) TTX inhibited the tonic contraction at significantly lower concentrations than it inhibited peak contraction. Thus, at low concentrations of TTX, a condition similar to that seen in obstructive hypertrophy was created. 4) The ED50 in the presence of atropine was significantly greater than the ED50 following ATP desensitization. This may indicate that there are separate synaptic elements for cholinergic and purinergic transmission. TTX blockade offers an interesting in vitro model to study the effects of neuropathy on the smooth muscle function.

The influence of streptozotocin-induced diabetes mellitus on the sensitivity of rat urinary bladder body and base strips to changes in extracellular calcium

1. 1. The influence of calcium on contractile responses of bladders from control and 2 month streptozotocin-diabetic rats was investigated. 2. 2. Removal of calcium from the bathing medium caused rapid decreases in the contractile responses of bladder body and base strips to carbachol. The responses of strips from control rats were reduced more by calcium removal than were strips from diabetics. 3. 3. Replacement of calcium caused dose-dependent increases in contraction to carbachol. The responses of bladder body strips from diabetic rats to carbachol were significantly greater at all calcium concentrations than were those of controls. There were no differences in the responsiveness of bladder base strips to carbachol. 4. 4. In contrast, bladder body strips from diabetic rats were more sensitive to calcium than were strips from controls, with an IC 50 value for calcium of 0.38 mM vs 0.72 mM for controls. 5. 5. At the calcium concentration of Krebs buffer (2.5 mM), contractile responses were near maximal, and there were no differences in sensitivity. 6. 6. The calcium antagonist nifedipine caused dose-dependent decreases in the contractile responses of bladder base and body strips to nerve stimulation. The responses to nerve stimulation were more sensitive to nifedipine than were those to carbachol. There were no differences between controls and diabetics in the sensitivity of bladder strips to nifedipine. 7. 7. The findings suggest that although increases in sensitivity to calcium are observed in bladder body strips from streptozotocin-diabetic rats, they are unlikely to be responsible for the increases in maximal contractile response to nerve stimulation and contractile agents.

Urinary Bladder Function 6 Months after the Onset of Diabetes in the Spontaneously Diabetic BB Rat

Urinary bladder function was examined in the spontaneously diabetic BB rat six months after the onset of diabetes. Diabetes caused significant decreases in rat weight and increases in bladder body weights and in vivo bladder capacities compared to age-matched controls, but no changes in the weights of bladder bases. The absolute contractile responses of urinary bladder body and base strips to nerve stimulation, carbachol, 5-hydroxytryptamine, ATP, phenylephrine, and KCl were unaltered by diabetes. However, when the data were corrected for tissue mass, there were slight but not significant decreases in contractile responses of strips from diabetic rats. There were increases in total muscarinic receptor numbers and calcium channel binding sites in bladder bodies from BB rats as a result of the increases in tissue mass. The data indicate that the six month-diabetic BB rat differs from the streptozotocin-diabetic rat in the sensitivity of the urinary bladder to the complications of diabetes, probably as a result of the insulin treatment required to keep BB rats alive.

Comparison of the Contractile and Metabolic Effects of Muscarinic Stimulation with Those of KC

Urinary bladder emptying is mediated primarily by a coordinated contraction of the bladder body in response to parasympathetic stimulation and muscarinic receptor activation. In previous studies we presented evidence that the contractile response to bethanechol stimulation could be dissociated from the metabolic response through the use of diltiazem (calcium channel blockade). The conclusion from these studies was that muscarinic stimulation resulted in a significant increase in metabolic activity which was not directly associated with contraction. KCl stimulates contraction in isolated strips by directly depolarizing the membrane rather than from binding to specific membrane receptors. The current study directly compares the metabolic and contractile activity of bethanechol (muscarinic stimulation) with KCl (direct membrane depolarization). Isolated strips of rabbit urinary bladder body were monitored in vitro for changes in intracellular-free calcium, NADH/NAD ratio, and contraction. Intracellular-free calcium was monitored by preincubation of isolated bladder smooth muscle strips with FURA-2 AM and continuously measuring the fluorescence with an MB2 surface spectrofluorometer using excitation wavelengths of 340 and 380 nm, and an emission wavelength of 510 nm. The NADH/NAD ratio was monitored with the MB2 surface spectrophotometer using an excitation wavelength of 366 nm and an emission wavelength of 450 nm. Contraction was monitored using a isometric force transducer connected to a Grass model D polygraph. The results can be summarized as follows. (1) Both bethanechol and KCl stimulate a sharp decrease in the NADH/NAD ratio, a rapid increase in intracellular-free calcium, and a slower increase in contractile force.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Pregnancy on Muscarinic Receptor Density and Function in the Rabbit Urinary Bladder

The contractile response of the rabbit urinary bladder to field stimulation consists of both cholinergic and purinergic components. In general, approximately 60% of the contractile response to field stimulation is cholinergic and 40% is purinergic. Although the purinergic response represents a significant proportion of the initial (phasic) pressure response to field stimulation of the isolated whole bladder, it contributes only 10-15% of the ability of field stimulation to empty the bladder. The current study investigates the effects of pregnancy on the contractile responses of the isolated urinary bladder to cholinergic and purinergic stimulation. The results of these studies indicate that pregnancy induces substantial changes in the physiology and pharmacology of the urinary bladder. The following data are consistent with the theory that pregnancy substantially increases the relative purinergic component of the response to field stimulation (and presumably neuronal stimulation): (1) there was a significantly greater response of the bladders isolated from pregnant rabbits to low-frequency field stimulation; (2) atropine was more effective at inhibiting the pressure generation of bladders isolated from virgin female rabbits; (3) field stimulation was more effective at emptying bladders isolated from virgin female rabbits; (4) the response of the bladders from pregnant rabbits to bethanechol was significantly reduced, whereas the response to ATP was significantly increased. In addition to these effects of pregnancy on bladder physiology, pregnancy induced a 50% decrease in the muscarinic receptor density of the urinary bladder body, which correlated very well with the 50% decrease in the contractile response to bethanechol.

Comparative length-tension relationship of urinary bladder strips from hamsters, rats, guinea-pigs, rabbits and cats

1. 1. Comparative passive tension-active tension curves were constructed for urinary bladder body strips from hamster, rat, guinea-pig, rabbit and cat. 2. 2. Equally sized strips from rabbit and cat bladders had a significantly greater mass and cross-sectional area than strips from other species. 3. 3. There was a greater change in cross-sectional area of strips from rabbit and cat bladders with increasing length than in strips from other species. 4. 4. Cat bladder strips developed a significantly greater absolute active tension than did strips from all other species at passive tensions greater than 5 g. 5. 5. The length-tension relationships of the urinary bladder differs from skeletal or vascular smooth muscle in that there is no significant decrease in active tension at strip lengths greater than L 0. 6. 6. The ability of the urinary bladder to generate active tension at tissue lengths considerably greater than L 0 is of prime importance in the physiological role of the urinary bladder to accommodate and store.

Biochemical characterization of the rabbit urinary bladder: II. Intracellular concentration of nucleotides

AbstractBladder contraction is mediated by a number of intracellular biochemical reactions including glycolysis, mitochondrial respiration, phosphocreatine kinase, and various ATPases. In order to understand how alterations in intracellular metabolism can affect bladder function (or how alterations in bladder function can affect intracellular metabolism), we must first understand and describe normal bladder metabolism. Using the rabbit as a model for bladder function, the present study compares the intracellular concentrations of a variety of important compounds between the bladder base and body.The intracellular concentrations of phosphocreatine (PC), creatine, ATP, ADP, and AMP were determined in samples of rabbit urinary bladder body and base. The values for PC and creatine were significantly lower in the bladder base than in the bladder body. Adenine nucleotide concentrations were similar in the two sections.The concentrations of NAD + NADH, NADP, CTP, CDP, CMP, GTP, GDP, GMP, and UTP, UDP, UMP were also measured. Of these compounds, the concentrations of GTP and UTP in the bladder body were nearly double those in the bladder base. The intracellular concentrations of the other tissue constituents were similar in the two bladder sections.These studies demonstrate that the bladder is not biochemically homogeneous but that the bladder base and body differ not only functionally but also metabolically.Experiments in which strips of bladder body were incubated in vitro in oxygenated Tyrode's solution containing glucose showed that the tissue concentrations of PC, ATP, GTP, and UTP decreased substantially following 30 min of incubation, with no further decrease during a subsequent 60‐min incubation.