Morphophysiological reaction of vital bush-like receptors of Rana temporaria to novocaine application

Morpho-physiological reaction of alive bush-like interoceptors in the Rana temporaria isolated urinary bladder to the effect of procaine hydrochloride (PH) solution (0.5 and 0.05%) has been studied. Total impulse activity of the receptors has been studied synchronously with changes occurring in their structures. The alive receptors are revealed by means of methylene blue in concentration 1.6 X 10(-4) mol/l. PH sharply inhibits the impulse activity which is completely damped under 0.05% solution nearly in 12-13 min, and at administration of 0.5% solution--in 1-2 min. The impulse amplitude is decreasing. Morphological and tinctorial shifts, produced by PH administration, appear later--in 15-20 min on the background of a completely inhibited impulse activity and are manifested as swelling and increasing size of terminal plates, formation of varicosities on the preterminals and in the region of the Ranvier node, deterioration of staining properties and their dynamic changes.     

Store-operated Ca2+ entry suppresses distention-induced ATP release from the urothelium

Epithelial cells in the urinary bladder (urothelium) trigger sensory signals in micturition by releasing ATP in response to distention of the bladder wall. Our previous study revealed the distinct roles of extracellular Ca(2+) and the Ca(2+) stores in the endoplasmic reticulum (ER) in urothelial ATP release. In the present study, we investigated the regulation of urothelial ATP release by Ca(2+) influx from the extracellular space and Ca(2+) release from the ER using a distention assay of the mouse bladder wall in a small Ussing chamber. Stimulation of Ca(2+) release from the ER in the mucosal side of the bladder induced significant ATP release without distention. Blockade of the inositol 1,4,5-triphosphate receptor reduced distention-induced ATP release, suggesting that Ca(2+) release from the ER is essential for the induction of urothelial ATP release. On the other hand, blockade of store-operated Ca(2+) entry (SOCE) from the extracellular space significantly enhanced distention-induced ATP release. Thus Ca(2+) release from the ER causes urothelial ATP release and depletion of Ca(2+) stores in the ER, which in turn causes the depletion-inducing SOCE to suppress the amount of urothelial ATP released.     

The role of volumetric feedback from the hindgut in the regulation of meal size in fifth-instar Locusta migratoria nymphs

ABSTRACT. Behavioural studies show that fullness of the hindgut influences the size of meals taken by fifth-instar Locusta migratoria L. nymphs, with the relevant information coming from the ileum and passing via the terminal abdominal ganglion. Morphological and electrophysiological studies suggest that stretch receptors on the posterior ileum, associated with branches of the rectal nerves, register extension of the ileal fold and probably also an increase in ileal volume. A system in which the volumetric feedbacks from both the crop and hindgut interact in the regulation of meal size is postulated.     

Contribution of the extracellular matrix to the viscoelastic behavior of the urinary bladder wall

We previously reported that when the stress relaxation response of urinary bladder wall (UBW) tissue was analyzed using a single continuous reduced relaxation function (RRF), we observed non-uniformly distributed, time-dependent residuals (Ann Biomed Eng 32(10):1409-1419, 2004). We concluded that the single relaxation spectrum was inadequate and that a new viscoelastic model for bladder wall was necessary. In the present study, we report a new approach composed of independent RRFs for smooth muscle and the extracellular matrix components (ECM), connected through a stress-dependent recruitment function. In order to determine the RRF for the ECM component, biaxial stress relaxation experiments were first performed on decellularized extracellular matrix network of the bladder obtained from normal and spinal cord injured rats. While it was assumed that smooth muscle followed a single spectrum RRF, modeling the UBW ECM required a dual-Gaussian spectrum. Experimental results revealed that the ECM stress relaxation response was insensitive to the initial stress level. Thus, the average ECM RRF parameters were determined by fitting the average stress relaxation data. The resulting stress relaxation behavior of whole bladder tissue was modeled by combining the ECM RRF with the RRF for the smooth muscle component using an exponential recruitment function representing the recruitment of collagen fibers at higher stress levels. In summary, the present study demonstrated, for the first time, that stress relaxation response of bladder tissue can be better modeled when divided into the contributions of the extracellular matrix and smooth muscle components. This modeling approach is suitable for prediction of mechanical behaviors of the urinary bladder and other organs that exhibit rapid tissue remodeling (i.e., smooth muscle hypertrophy and altered ECM synthesis) under various pathological conditions.     

Peculiarities of Signal Transduction from Arginine-Vasopressin Receptors Located on the Apical Surface of Epithelial Cells of the Frog Urinary Bladder and on the Amoeba Outer Membrane

Mechanisms of action of arginine-vasopressin (AVP) on water transport across the wall of urinary bladder of the frog R. temporaria L. and the outer membrane of the amoeba A. proteus were considered. AVP and its functional analogs were added to the basolateral and apical surfaces of the frog urinary bladder membrane and to the amoeba outer surface. In amoeba the AVP effect was evaluated from action on frequency of contractions of contractile vacuole that represents its organ of water—electrolyte homeostasis. It was shown that the system of signal transduction from the apical AVP receptors differed considerably from that located on the basolateral membrane and had a marked similarity with the system of signal transduction from AVP-sensitive structures on the outer membrane of amoeba. The urinary bladder apical membrane as well as the amoeba outer membrane has a mixed type of sensitivity to AVP with unidirectional (not antagonistic like on the basolateral membrane) involvement of systems coupled to receptors of the V₁ and V₂ type. We suggest that the system of signal transduction from apical AVP receptors corresponds to the earlier stage of evolutionary development.     

Structuro-functional changes of bushy receptors after reoxygenation

With restarting oxygen supply to the bushy receptors of the frog urinary bladder, a gradual increase of impulse frequency in the afferent neural fibers is observed, with a successive exceed, in some cases, of the initial level and rearrangement of spike rhythmicity according to the type of "spasmodic" discharges. Certain acceleration is noted in vital staining and discoloration of the receptors. This is expressed in shortening coloration time, in increasing rate for accumulation restorative equivalents, in intensified granuloformation. Ultrastructural shifts are mainly demonstrated in normalization of the mitochondrial apparatus.     

Structuro-functional changes in bushy interoceptors during protracted anoxia

The bushy receptors of the frog urinary bladder respond to the effect of 60-minute-long anoxia with a complex combination of morphological. tinctorial and electrophysiological reactions. A biphase change in dynamics of bioelectrical activity takes place (an initial increase of frequency with its successive decrease), prolongation of the vital staining periods with methylene blue, change in the character of staining and decoloration of the receptory plates: increase in homogeneity and in intensity of staining, discontinuance of granuloformation and weakening of processes of the plates mobility. The ultrastructural changes are mainly concerned with mitochondria, where either crists reduce and osmiophility decreases, or increases. A part of mitochondria does not change. Certain heterogeneity in reactive changes of the receptors is noted. This is considered as manifestation of functional heterogeneity of the receptory units and their structural elements.     

Lymphoid nodules of the urinary bladder in man

Basing on macro- microscopical investigation of the urinary bladder in 94 persons, died at the period of birth up to old years and by the time of death having not any disease of the urinary apparatus, structure and topography of the lymphoid nodules, their amount, density of distribution in the mucous membrane of various parts of the organ have been studied. The germinative centers in the lymphoid nodules of the urinary bladder are not revealed. The external appearance of the nodules is not the same; some have clear contours others have no clearly manifested borders. We call them prenodules. The lymphoid nodules are situated near to each other without any definite order. And only near the ureteral openings they are always revealed in a small amount, in the area of the triangle; they are oriented, as a rule, from the ureteral openings towards the exit from the urinary bladder. The amount of the lymphoid nodules in the organ's wall varies (at an average) from 18, in newborns, up to 415, in adolescents, and up to 129, in old persons. Distribution density of the lymphoid nodules in the fundal area of the urinary bladder is somewhat greater, than in its superior parts. The size of the lymphoid nodules during all age periods is not more than 900 mcm.     

Quantifying whole bladder biomechanics using the novel pentaplanar reflected image macroscopy system

Optimal bladder compliance is essential to urinary bladder storage and voiding functions. Calculated as the change in filling volume per change in pressure, bladder compliance is used clinically to characterize changes in bladder wall biomechanical properties that associate with lower urinary tract dysfunction. But because this method calculates compliance without regard to wall structure or wall volume, it gives little insight into the mechanical properties of the bladder wall during filling. Thus, we developed Pentaplanar Reflected Image Macroscopy (PRIM): a novel ex vivo imaging method to accurately calculate bladder wall stress and stretch in real time during bladder filling. The PRIM system simultaneously records intravesical pressure, infused volume, and an image of the bladder in five distinct visual planes. Wall thickness and volume were then measured and used to calculate stress and stretch during filling. As predicted, wall stress was nonlinear; only when intravesical pressure exceeded ~ 15 mmHg did bladder wall stress rapidly increase with respect to stretch. This method of calculating compliance as stress vs stretch also showed that the mechanical properties of the bladder wall remain similar in bladders of varying capacity. This study demonstrates how wall tension, stress and stretch can be measured, quantified, and used to accurately define bladder wall biomechanics in terms of actual material properties and not pressure/volume changes. This method is especially useful for determining how changes in bladder biomechanics are altered in pathologies where profound bladder wall remodeling occurs, such as diabetes and spinal cord injury.

     

Effect of chronic capsaicin treatment on tachykinin NK1 binding sites in the rat.

Binding sites for [125I]-Bolton-Hunter substance P (BHSP) were investigated in homogenates of rat submandibular gland, colon smooth muscle, and urinary bladder. In vehicle-treated animals, the equilibrium dissociation constant (KD) was similar for both submandibular gland (0.46 +/- 0.03 nM) and colon (0.57 +/- 0.04 nM), although the maximum density of binding sites (Bmax) was about six-fold higher in submandibular gland compared with colon. These binding parameters remained unchanged in capsaicin-pretreated animals (140 mg/kg IP). In contrast, capsaicin pretreatment reduced (p less than 0.05) the Bmax in urinary bladder by twenty-five percent (0.56 fmol/mg wet weight) when compared to vehicle-treated controls (0.73 fmol/mg wet weight), although the KD was unchanged (vehicle, 0.29 +/- 0.08 nM; capsaicin, 0.24 +/- 0.04 nM). These data demonstrate that the NK1 receptors in submandibular gland and colon smooth muscle are not associated with or dependent upon intact primary afferent sensory neurons. However, a minority of NK1 receptors in the urinary bladder were lost after capsaicin, indicating that these receptors are located on sensory terminals, or may be dependent on growth factors or other chemicals released from these nerves.     

Vascular response of the rabbit bladder to chronic partial outlet obstruction

Partial outlet obstruction of the rabbit urinary bladder results, initially, in a rapid increase in bladder mass and remodeling of the bladder wall. Previously, it was shown that this response was characterized by serosal growth (thickening) which was apparent after 1 day of obstruction, before any visible vascularization was observed. After 1 week of obstruction, significant microvessel formation was seen in the transition region between the detrusor smooth muscle and the thickening serosa; after 2 weeks the entire serosa was vascularized.In this study we investigated the effect of chronic (4 week) partial outlet obstruction on microvessel density and distribution in the bladder wall immunohistochemically using CD31 as a marker for vascular endothelium. Transverse sections of bladder wall were examined after 4 weeks of no surgery, sham surgery or partial obstruction.The microvessel density of the obstructed rabbit bladder mucosa and detrusor smooth muscle increased relative to augmentation of these compartments while new vessels appeared in the thickening serosa. Although vessel density did not change with obstruction a significant shift in mean vessel circumference to the left occurred indicating a significant increase in the number of microvessels and small vessels consistent with angiogenesis.     

Myxobolus cuneus n. sp. (Myxosporea) infecting the connective tissue of Piaractus mesopotamicus (Pisces: Characidae) in Brazil: histopathology and ultrastructure

The characteristics of Myxobolus cuneus n. sp. and its relationship to the host Piaractus mesopotamicus are described based on light and electron microscopy and histological observations. Polysporic plasmodia measuring 20 microm to 2.1 mm in size were found in 63.3 % of the P. mesopotamicus examined. The parasite was found in the gall bladder, urinary bladder, gills, spleen, fins, head surface, liver and heart. Generative cells and disporoblastic pansporoblasts occurred along the periphery of the plasmodia, and mature spores were found in the internal region. The mature spores had a pear shaped body in frontal view, with a total length of 10.0 +/- 0.6 microm and a width of 5.1 +/- 0.3 microm (mean +/- SD). The spore wall was smooth with sutural folds. The polar capsules were elongated, were pear shaped, and equal in size (length 5.7 +/- 03 microm; width 1.7 +/- 0.2 microm), with the anterior ends close to each other. The polar filaments were tightly coiled in 8-9 turns perpendicular to the axis of the capsule. The plasmodia were always found in connective tissue (wall of the arterioles of the gill filaments, serous capsule of the gall bladder, middle layer and subepithelial connective tissue of the urinary bladder, connective tissue between the rays of the fins, subcutaneous tissue of the head surface and fibrous capsule spleen). The parasite caused important damage in the gills, where development occurred in the wall of gill filament arterioles; a mild macrophage infiltrate was also observed. In advanced developmental stages, the plasmodia caused deformation of the arteriole structure, with a reduction and, in some cases, obstruction of the lumen. The parasite was found throughout the period studied and its prevalence was unaffected by host size, season or water properties.     

Satellite glial cell P2Y12 receptor in the trigeminal ganglion is involved in lingual neuropathic pain mechanisms in rats

Background

Interstitial cystitis/painful bladder syndrome (IC/PBS), is a severely debilitating chronic condition that is frequently unresponsive to conventional pain medications. The etiology is unknown, however evidence suggests that nervous system sensitization contributes to enhanced pain in IC/PBS. In particular, central nervous system plasticity of glutamatergic signaling involving NMDA and metabotropic glutamate receptors (mGluRs) has been implicated in a variety of chronic pain conditions. Here, we test the hypothesis that mGluR5 mediates both non-inflammatory and inflammatory bladder pain or nociception in a mouse model by monitoring the visceromotor response (VMR) during graded bladder distention.

Results

Using a combination of genetic and pharmacologic approaches, we provide evidence indicating that mGluR5 is necessary for the full expression of VMR in response to bladder distention in the absence of inflammation. Furthermore, we observed that mice infected with a uropathogenic strain of Escherichia coli (UPEC) develop inflammatory hyperalgesia to bladder distention, and that the selective mGluR5 antagonist fenobam [N-(3-chlorophenyl)-N'-(4,5-dihydro-1-methyl-4-oxo-1H-imidazole-2-yl) urea], reduces the VMR to bladder distention in UPEC-infected mice.

Conclusions

Taken together, these data suggest that mGluR5 modulates both inflammatory and non-inflammatory bladder nociception, and highlight the therapeutic potential for mGluR5 antagonists in the alleviation of bladder pain.     

Neo-regeneration of urinary bladder: a desired metaplasia of autologous membrane from rectosigmoid colon containing stem cells of intestinal crypts

The current management of diseases of urinary bladder requiring resection is by augmentation cystoplasty or transplantation of ureters. Transplantation of ureters is associated with morbidity and mortality. Ideal management will be by regenerating urinary bladder in vivo. Neo-regeneration of tissues and organs like abdominal wall, aponeurosis etc., has been attempted and patented. After neo-regeneration of mesoderm tissues and organs, regeneration of urinary bladder (developed from endoderm) was. In vivo surgical techniques were developed in dogs. It is known that the embryonic morphogenesis of urinary bladder is from uro-genital sinus of hind gut. A membrane, containing endoderm stem cells in crypts of recto-sigmoid colon, was surgically isolated and colonized with remnant of urinary bladder wall after extensive resection. Experimental study was performed in dogs, for 60 days to one and a half year. Regeneration of all the layers of tissues of the wall of urinary bladder was observed. The neo-regeneration phenomenon has been recognized as "desired metaplasia". The regenerated neo tissue/organ on histological examination and cystometry studies was found compatible with normal urinary bladder. The hypothesis, neo-regeneration and desired metaplasia, is discussed.     

Comparative quantitative assessment of GnRH- and LH-receptor mRNA expression in the urinary tract of sexually intact and spayed female dogs

Ovariectomy interrupts the regulatory loop in the hypothalamus-pituitary-gonad axis, leading to a several-fold increase in gonadotropin levels. This rise in hormonal secretion may play a causal role in ovariectomy-related urinary incontinence. The purpose of this study was to examine the effect of ovariectomy in bitches on the expression of GnRH- and LH-receptors in the lower urinary tract, and assess the relationship between receptor expression and plasma gonadotropin concentrations. Plasma gonadotropins were measured in 37 client-owned bitches. Biopsies were harvested from the mid-ventral bladder wall in all dogs, and from nine further locations within the lower urinary tract in 17 of the 37 animals. Messenger RNA of the LH and GnRH receptors was quantified using RT-PCR with the TaqMan Universal PCR Master Mix. Gonadotropins were measured with a canine-specific FSH-immunoradiometric assay and LH-radioimmunoassay. The hierarchical mixed ANOVA model using MINITAB, Mann-Whitney U-test, unpaired means comparison and linear regressions using StatView were applied for statistical analyses. Messenger RNA for both receptors was detected in all biopsy samples. Age was negatively correlated to mRNA expression of the LH and the GnRH receptors. A relationship between the mRNA values and the plasma gonadotropin concentrations was not established. Evaluation of results within each of the biopsy locations revealed greater LH-receptor expression in the proximal second quarter of the urethra in spayed bitches than in intact bitches (P=0.0481). Increased mRNA expression of LH receptors in this location could possibly play a role in the decrease in closing pressure of the urethra following ovariectomy.     

Excitatory GABAA receptor in autonomic pelvic ganglion neurons innervating bladder

Major pelvic ganglia (MPG) are relay centers for autonomic reflexes such as micturition and penile erection. MPG innervate the urogenital system, including bladder. γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system, and may also play an important role in some peripheral autonomic ganglia, including MPG. However, the electrophysiological properties and function of GABA_A receptor in MPG neurons innervating bladder remain unknown. This study examined the electrophysiological properties and functional roles of GABA_A receptors in bladder-innervating neurons identified by retrograde Dil tracing. Neurons innervating bladder showed previously established parasympathetic properties, including small membrane capacitance, lack of T-type Ca²⁺ channel expression, and tyrosine-hydroxylase immunoreactivity. GABA_A receptors were functionally expressed in bladder innervating neurons, but GABA_C receptors were not. GABA elicited strong depolarization followed by increase of intracellular Ca²⁺ in neurons innervating bladder, supporting the hypothesis GABA may play an important role in bladder function. These results provide useful information about the autonomic function of bladder in physiological and pathological conditions.     

Ex vivo deformations of the urinary bladder wall during whole bladder filling: Contributions of extracellular matrix and smooth muscle

As the complete understanding of urinary bladder function requires knowledge of organ level deformations, we conducted ex vivo studies of surface strains of whole bladders during controlled filling. The surface strains derived from displacements of surface markers applied to the posterior surface of excised rat bladders were tracked under slow filling with pressure and volume simultaneously recorded in the passive and completely inactivated states (i.e. with and without smooth muscle tone, respectively). Bladders evaluated in the passive state exhibited spontaneous contractions and larger average peak pressures (16.7 mmHg compared to 6.4 mmHg in the inactive state). Overall, the bladders exhibited anisotropic deformations and were stiffer in the circumferential direction, with average peak stretch values of ～2.3 and ～1.9 in the longitudinal and circumferential directions, respectively, for both states. Although bladders in the passive state were stiffer, they had similar average peak areal stretches of 4.3 in both states. However, differences early in the filling process as a result of a loss in smooth muscle tone in the inactive state resulted in longitudinal lengthening of 36%. Idealizing the bladder as a prolate spheroid, we estimated the wall stress–strain relation during filling and demonstrated that the intact bladder exhibited the classic stress–stretch relation, with a significantly protracted low stress region and peak stresses of 36 and 51 kPa in the longitudinal and circumferential directions, respectively. The present study fills a major gap in the urinary bladder biomechanics literature, wherein knowledge of the pressure–volume–wall stress–wall strain relation was explored for the first time in a functioning organ ex vivo.     

A biomechanical model to assess the contribution of pelvic musculature weakness to the development of stress urinary incontinence

A biomechanical model of the female pelvic support system was developed to explore the contribution of pelvic floor muscle defect to the development of stress urinary incontinence (SUI). From a pool of 135 patients, clinical data of 26 patients with pelvic muscular defect were used in modelling. The model was employed to estimate the parameters that describe the stiffness properties of the vaginal wall and ligament tissues for individual patients. The parameters were then implemented into the model to evaluate for each patient the impact of pelvic muscular defect on the vaginal apex support and the bladder neck support, a factor that relates to the onset of SUI. For the modelling analysis, the compromise of pelvic muscular support was demonstrated to contribute to vaginal apex prolapse and bladder neck prolapse, a condition commonly seen in SUI patients, while simulated conditions of restored muscular support were shown to help re-establish both vaginal apex and bladder neck supports. The findings illustrate the significance of pelvic muscle strength to vaginal support and urinary continence; therefore, the clinical recommendation of pelvic muscle strengthening, such as Kegel exercises, has been shown to be an effective treatment for patients with SUI symptoms.     

Characterization of bradykinin receptors in peripheral organs.

Bradykinin (BK) and related kinins are potent stimulants of the rabbit jugular vein, the hamster urinary bladder, and the guinea pig trachea. The characterization of kinin receptors in these tissues was made with agonists and antagonists. Results obtained with agonists indicate that bradykinin and kallidin are much more active than des-Arg9-BK and suggest the presence of B2 receptors in the three organs. Some new agonists were also tested and the BK analogue, [Hyp3,Tyr(Me)8]BK, was found to be a potent and selective stimulant of the three preparations, with pD2 values of 8.56, 8.00, and 8.39, respectively, but inactive on the rabbit aorta (a B1-receptor system). Contractile effects of kinins in the rabbit jugular vein and hamster urinary bladder were reduced or eliminated by B2-receptor antagonists but at different concentration levels; e.g., acetyl-D-Arg[Hyp3,D-Phe7]BK showed pA2 values of 7.78 on the rabbit jugular vein but only 5.72 on hamster urinary bladder. This compound contracted the guinea-pig trachea and was found to be inactive as an antagonist on this preparation. Contractions of the hamster urinary bladder and the guinea-pig trachea in response to bradykinin were markedly reduced or eliminated by indomethacin and by BW 755C, while those of the rabbit jugular vein were not modified. The present findings indicate that the myotropic effect of kinins on the rabbit jugular vein depends on the activation of B2 receptors and suggest that B2 receptors are largely responsible also for the response of the hamster urinary bladder. B2 receptors and (or) a nonreceptor mechanism appear to be involved in the stimulant effects of the kinin agonists and some antagonists in the guinea-pig trachea.     

Preparation of the spinal neurons and their bushy receptors for morphophysiological study

A preparation of the sensory neuron of the spinal ganglion with dendritic processes for simultaneous morphological and physiological investigations is described. It consists of a frog urinary bladder with bushy interoceptors in its wall, two vesicle neurons, two abdominal branches of the X spinal nerves and two IX spinal ganglia with ventral and dorsal roots branching off from them. The total length from the receptors to the ganglion neurons is 20-30 mm. In the ganglia a zone of the neuronal bodies localization is found, their processes form receptors; the zone includes as many as 9 neurons, 50-80 mkm in size. A vital fine structure of the ganglion cells and their satellites is traced. There are three types of cells in the ganglion--large, middle and small. Electrophysiological control has demonstrated that the preparation is viable for several hours.