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PubMed1998

Expression and localization of epithelial sodium channel in mammalian urinary bladder.

The mammalian urinary bladder exhibits transepithelial Na+ absorption that contributes to Na+ gradients established by the kidney. Electrophysiological studies have demonstrated that electrogenic Na+ absorption across the urinary bladder is mediated in part by amiloride-sensitive Na+ channels situated within the apical membrane of the bladder epithelium. We have used a combination of in situ hybridization, Northern blot analysis, and immunocytochemistry to examine whether the recently cloned epithelial Na+ channel (ENaC) is expressed in the rat urinary bladder. In situ hybridization and Northern blot analyses indicate that alpha-, beta-, and gamma-rat ENaC (rENaC) are expressed in rat urinary bladder epithelial cells. Quantitation of the levels of alpha-, beta-, and gamma-rENaC mRNA expression in rat urinary bladder, relative to beta-actin mRNA expression, indicates that, although comparable levels of alpha- and beta-rENaC subunits are expressed in the urinary bladder of rats maintained on standard chow, the level of gamma-rENaC mRNA expression is 5- to 10-fold lower than alpha- or beta-rENaC mRNA. Immunocytochemistry, using an antibody directed against alpha-rENaC, revealed that ENaCs are predominantly localized to the luminal membrane of the bladder epithelium. Together, these data demonstrate that ENaC is expressed in the mammalian urinary bladder and suggest that amiloride-sensitive Na+ transport across the apical membrane of the mammalian urinary bladder epithelium is mediated primarily by ENaC.

Animals↗
PubMed1983

Changes in length and volume of smooth muscle cells of the hypertrophied rat urinary bladder.

Rat urinary bladders were denervated by bilateral excision of the pelvic ganglion. After 10 days the hypertrophied bladders were removed, filled with 0.75 ml Krebs solution, fixated and embedded for electron microscopy. Normal bladders filled with the same volume were used as controls. Tangential and transverse sections of longitudinal muscle bundles were cut both for phase contrast and electron microscopy. The profiles of cross-sectioned cells from control bladders had regular, often almost circular contours, and were rather uniform in size. The cell contours from the denervated bladders were irregular with wrinkled surfaces and the cells varied considerably in size. In tangential sections the cells from denervated bladders had corrugated surfaces in contrast to the control cells. Mean length and volume of the muscle cells were determined morphometrically. Whereas cell volume was larger in denervated (3 800 microns 3) than in control bladders (2 200 mu 3), cell length was less (226 versus 335 microns). The finding of shorter cells in denervated bladders favour the opinion, brought forward previously (Ekström & Uvelius 1981), that the rightward shift of the active length-tension curve in denervated bladders is due to an increase in the number of muscle cells that are coupled in series around the bladder circumference.

Animals↗
PubMed1981

A finite deformation theory of intravesical pressure and mural stress of the urinary bladder.

The urinary bladder is assumed to be an incompressible isotropic material like a rubber. Then, by making use of the finite deformation theory for such a hyperelastic continuum, we have calculated the intravesical pressure and the mural stress of the bladder as a function of its volume. The formula for the mural stress contains two parameters. These parameters are determined by the uniaxial extension test of the dog bladder sample. The calculation result shows that the pressure is relatively flat while the stress continues to rise with the volume. This is the typical behavior in the normal living cystometrogram. From these analysis, therefore, we conclude that such a behavior comes from the elasticity of the bladder itself, and requires no explanation in terms of reflex inhibitory relaxation.

Elasticity↗
PubMed2004

The effect of pregnancy and the oestrus cycle on purinergic and cholinergic responses of the rat urinary bladder.

The urinary bladder undergoes plastic changes during physiological alterations such as pregnancy. This study has shown that bladders from pregnant rats weighed three times more than bladders from virgin rats. Each milligram of detrusor muscle from pregnant rats contracted more strongly to nerve stimulation (150% greater) and agonists (50% greater or more) compared to detrusor from virgin rats at any stage during the oestrus cycle. The purinergic component of nerve-mediated responses altered during the oestrus cycle, being greatest during oestrus (oestrogen and progesterone fall rapidly) and dioestrus (low oestrogen and progesterone), smaller during pregnancy and even smaller during pro-oestrus (high oestrogen and progesterone); in contrast the cholinergic component remained relatively unchanged. In conclusion, during pregnancy the detrusor muscle generates larger contractions compared to virgin detrusor muscle, probably due to hormonal influences on smooth muscle contraction mechanisms. As agonist responses were unchanged during the oestrus cycle, changes in the purinergic component of nerve stimulation was not due to altered P2 receptor expression but possibly to an increase in ATP release or a reduction in breakdown. The hormonal effect may have implications for the treatment of bladder disorders due to alterations in hormones, such as stress incontinence in post-menopausal women.

Animals↗
PubMed1980

PAH transport in rock crab (Cancer irroratus) urinary bladder.

Crab urinary bladder appears to possess several morphological and functional similarities to vertebrate renal proximal tubule. Sections of intermolt rock crab bladder accumulated PAH by a process that was concentrative (60 min tissue-to-medium ratio (T/M) for 10 microM PAH averaged 24), Na dependent, powered by glycolytic metabolism, and inhibitable by other organic anions. Initial section uptakes exhibited saturation kinetics and a double-reciprocal plot of uptake vs. concentration yielded a single line with a Km of 70 microM and a Vmax of 5 nmol . mg tissue-1 . h-1. Chlorophenol red and bromocresol green (BCG) competitively inhibited PAH uptake. When bladder sheets were mounted in a flux chamber, they exhibited a large, net lumen-to-serosa (L leads to S) flux of 10 microM PAH that was abolished by 1 mM BCG. The small unidirectional S leads to L flux was not BCG-inhibitable. Bladder sheets exhibited PAH T/M greater than 1 after luminal, but not serosal, exposure. BCG only reduced bladder sheet T/M after luminal exposure. The data are consistent with uphill, Na-dependent, and carrier-mediated entry of PAH at the luminal membrane and nonmediated exit at the serosal membrane.

Aminohippuric Acids↗
PubMedDate not supplied

Urinary bladder carcinogenesis.

Urinary bladder carcinogenesis in rodents bears numerous similarities to the diseases in humans. In rats, the process progresses through the morphologic stages of simple hyperplasia, papillary and nodular hyperplasia, papilloma, noninvasive, and invasive carcinoma. In mice, the pathogenesis can be similar or can follow a sequence of marked dysplasia with or without hyperplasia, leading to carcinoma in situ and ultimately to high-grade invasive carcinoma. Although the papillary and nonpapillary diseases appear to be related in rodents and in humans, they are distinct morphologically, biologically, and molecularly. Numerous classes of genotoxic chemicals have been identified as bladder carcinogens in rodents, and some of these have also been identified as carcinogenic in humans, most notably, aromatic amines, nitrosamines, and cyclophosphamide. In contrast, nongenotoxic chemicals appear to be highly specific with respect to species, strain, diet, agent, dose, and mechanism. For some, it is unclear whether the results at high doses in rodents can be extrapolated to low doses or to humans, e.g., chemicals that cause bladder cancer only at high doses related to the formation of calculi. Numerous observations in rodents can assist in identifying possible mechanisms involved for these nongenotoxic chemicals and therefore can be important for a rational evaluation of human risk.

Amines↗
PubMed1982

Cellular lithium and transepithelial transport across toad urinary bladder.

Toad urinary bladders were exposed on either their mucosal or serosal surfaces, or on both surfaces, to medium in which sodium was replaced completely by lithium. With mucosal lithium Ringer's, serosal sodium Ringer's, short-circuit current (SCC) declined by about 50 percent over the first 60 min and was then maintained over a further 180 min. Cellular lithium content was comparable to the sodium transport pool. With lithium Ringer's serosa, SCC was abolished over 60 to 120 min whether the mucosal cation was sodium or lithium. Measurements of cellular ionic composition revealed that the epithelial cells gained lithium from both the mucosal and serosal media. With lithium Ringer's mucosa and serosa, cells lost potassium and gained lithium and a little chloride and water, but these changes in cellular ions could not account for the current flow across the tissue under these conditions, which must, therefore, have been carried by a transepithelial movement of lithium itself. The inhibition by serosal lithium of SCC was overcome by exposure of the mucosal surface of the bladders to amphotericin B. Thus it reflected, predominantly, an inhibition of lithium entry to the cells across the apical membrane. It is suggested that this inhibition is a consequence of cellular lithium accumulation.

Amiloride↗
PubMed1999

[Measurement of boundary line of urinary bladder and peritoneum in abdominal wall and the application in performing cesarean section with urinary bladder reversal method].

OBJECTIVE: To provide the basic research data and clinical application in performing extraperitoneal cesarean section (CS) with urinary bladder reversal method. METHODS: The position and the surface projection of the vesico-peritoneal fold and the apex of the urinary bladder were measured in 107 cases of term pregnant women (37-42 weeks, aged 20-40). RESULTS: The distance from the bladder apex to the umbilicus and to the symphysis pubis were (14.1 +/- 3.4) cm and (6.8 +/- 1.4) cm respectively, while from the utero-vesical pouch to umbilicus and symphysis pubis were (15.8 +/- 3.9) cm and (4.9 +/- 1.5) cm respectively. During late pregnancy the projection of bladder apex was located at the point between the middle and the lower 1/3 of the line from umbilicus to symphysis pubis; while the utero-vesical pouch was located at the point between upper 3/4 and the lower 1/4 of the same line. The time interval from the start of operation to the delivery of baby was (14.56 +/- 6.3) min, and the total operation period was (45.5 +/- 9.3) min. The largest baby weighed 5,050 gm and there was no bladder injury. CONCLUSION: To define the position of vesical peritoneal fold would give benefit to the extraperitoneal CS with bladder reversal method which was performed under direct visualization and could avoid injury of bladder.

Adult↗
PubMed2002

Inhibitory control of the urinary bladder in the neonatal rat in vitro spinal cord-bladder preparation.

Urinary bladder activity of the neonatal rat is tonically inhibited by neural input from the spinal cord passing through axons in the pelvic nerve. The present study was undertaken to examine the organization of this inhibitory mechanism using in vitro spinal cord-bladder preparations of neonatal rats in which the lumbosacral dorsal roots (DRs) or ventral roots (VRs) were transected. Isovolumetric bladder contractions occurring spontaneously or induced by electrical stimulation of the bladder wall (ES-BW) were measured. In DR transected (DRT) preparations, removal of the spinal cord significantly enhanced (50-59%) the amplitude of spontaneous and ES-BW-evoked bladder contractions; whereas in VR transected (VRT) preparations removal of the spinal cord produced only a small enhancement (6.7-12%). However, in VRT preparations, electrical stimulation of the dorsal roots reduced the amplitude of spontaneous contractions, an effect blocked by a nicotinic ganglionic blocking agent, hexamethonium. In DRT preparations, MK-801 enhanced the amplitude of spontaneous and ES-BW-evoked contractions. These results demonstrate that bladder activity of the neonatal rat is tonically inhibited by input from the lumbosacral spinal cord via parasympathetic pathways in the pelvic nerve. The inhibitory outflow is not dependent upon afferent input to the cord but is facilitated by NMDA glutamatergic transmission in the spinal cord. Antidromic activation of afferent axons also appears to induce inhibition in the bladder via a mechanism involving nicotinic cholinergic receptors. These findings suggest that spinal and peripheral inhibitory mechanisms may play an important role in controlling voiding in the neonatal rat.

Animals↗
PubMed2004

Oxidant driven signaling pathways during diabetes: role of Rac1 and modulation of protein kinase activity in mouse urinary bladder.

BACKGROUND: Urinary bladder dysfunction is a complication in diabetes but the mechanisms involved are undefined. Here, we investigated roles of oxidative stress and oxidant driven signaling pathways in a murine model of diabetes, with an emphasis on urothelial vs. smooth muscle regional changes. METHODS: Mice were dosed with streptozotocin (150 mg/kg) or vehicle and studied at 5 weeks. Functional changes were assessed by in vitro cystometry. Immunohistochemical methods and automated digital imaging was used for morphometric and histochemical analysis of bladder tissue regions. RESULTS: We detected significant increases in protein 3-nitrotyrosine in both urothelium and smooth muscle regions during diabetes, demonstrating an increased prevalence of reactive nitrogen species. In light of nitric oxide synthase (NOS) isoforms as potential contributors to increased protein nitration, all three NOS isoforms were studied; region specific increases in NOS1 (urothelium and smooth muscle), NOS2 (urothelium only) but no alterations in NOS3 isoform were detected during diabetes. In contrast, p21-Rac1 (coordinating protein of NADPH oxidase) was significantly increased only in smooth muscle (diabetic vs. controls). We also investigated phosphorylation of ERK, JNK, p38 and Akt using immunohistochemical techniques; each of these was increased during diabetes but with different distributions in the two major regions of bladder tissues viz the smooth muscle and urothelium. CONCLUSIONS: The STZ mouse model of diabetes exhibits bladder dysfunction and structural changes similar to human. Reactive nitrogen species formation occurs in this setting and region specific assessments also revealed that urothelial changes and smooth muscle changes are discrete with respect to mechanisms of reactive nitrogen species (increased production of NO vs. superoxide anion) and activation of oxidant related stress signaling pathways.

Animals↗
PubMed1989

Organic anion and cation transport in crab urinary bladder.

Crab urinary bladder, a simple, flat-sheet epithelium, is structurally and functionally analogous to vertebrate renal proximal tubule. Like proximal tubule, crab bladder plays an important role in the excretion of potentially toxic, charged metabolites and xenobiotics. Bladders from Cancer borealis secrete monovalent, organic anions and cations in vivo and in vitro. For organic cations, secretion is a two-step process, with mediated and energetically downhill uptake into cells at the serosal membrane and uphill exit at the luminal membrane. The uptake step may be driven by the electrical potential difference across the serosal membrane, the luminal step by organic cation-proton exchange. Monovalent organic anions are also secreted by a separate two-step process. Recent experiments with intact bladder tissue and isolated membrane vesicles show that (as in mammalian proximal tubule) uphill serosal uptake can be coupled indirectly to the Na+ gradient. Organic anion (p-aminohippurate; PAH) uptake is driven by exchange for certain divalent organic anions, e.g., glutarate and alpha-ketoglutarate. The divalent anion gradient (in greater than out) is in turn maintained by Na+-coupled divalent uptake. The PAH exist step at the luminal membrane is mediated and downhill; it may involve anion exchange.

Animals↗
PubMed1988

Effect of bethanechol on glycolysis and high energy phosphate metabolism of the rabbit urinary bladder.

The urinary bladder, similar to other smooth muscles, utilizes glucose as one of its primary sources of metabolic energy. We have studied the effect of bethanechol on both glycolysis and high energy phosphate metabolism. The results can be summarized as follows: bethanechol administration in vitro stimulates a 30% decrease in intracellular glycogen, a 100% increase in lactic acid production, and an 80% increase in CO2 generation. Although there was a rapid and sustained decrease in the intracellular concentration of creatine phosphate, there was only a minor decrease in the intracellular concentration of ATP. There were no changes in adenine uptake or de novo ATP synthesis.

Adenine↗
PubMed1986

Prostate-specific acid phosphatase immunoreactivity in adenocarcinomas of the urinary bladder.

Fifteen urinary bladder adenocarcinomas and nine bladder tumors with mixed glandular and transitional features were studied with antisera to prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PSAP). The study was repeated with antisera from different companies to assess the reproducibility of the results. Of the 11 adenocarcinomas in men, three were positive for PSAP. Of the five tumors with mixed glandular and transitional features in men, one showed PSAP immunoreactivity. In the female subjects, PSAP staining was seen in two of the four adenocarcinomas and two of the four mixed glandular and transitional cell carcinomas. None of the tumors seen in either the male or female groups was considered positive for PSA.

Acid Phosphatase↗
PubMed1987

Characterization of the basolateral membrane conductance of Necturus urinary bladder.

Necturus urinary bladders stripped of serosal muscle and connective tissue were impaled through their basolateral membranes with microelectrodes in experiments that permitted rapid changes in the ion composition of the serosal solution. The transepithelial electrical properties exhibited a marked seasonal variation that could be attributed to variations in the conductance of the shunt pathway, apical membrane selectivity, and basolateral Na+ transport. In contrast, the passive electrical properties of the basolateral membrane remained constant throughout the year. The apparent transference numbers (Ti) of the basolateral membrane for K+ and Cl- were determined from the effect on the basolateral membrane equivalent electromotive force of a sudden increase in the serosal K+ concentration from 2.5 to 50 mM/liter or a decrease in the Cl- concentration from 101 to 10 mM/liter. TK and TCl were 0.71 +/- 0.05 and 0.04 +/- 0.01, respectively. The basolateral K+ conductance could be blocked by Ba2+ (0.5 mM), Cs+ (10 mM), or Rb+ (10 mM), but was unaffected by 3,4-diaminopyridine (100 microM), decamethonium (100 microM), or tetraethylammonium (10 mM). We conclude that a highly selective K+ conductance dominates the electrical properties of the basolateral membrane and that this conductance is different from those found in nerve and muscle membranes.

4-Aminopyridine↗