Release Of Chemical Mediators Research Articles

Evaluation of antiallergic and anti-anaphylactic activity of ethanolic extract of Sanseveiria trifasciata leaves (EEST) in rodents

Aim of the studyThe leaves and rhizomes of Sansevieria trifasciata are used in folk medicine for treating bronchitis, asthma, cough, snake bite and insect bite etc. The ethanolic extract elicited analgesic, anti-inflammatory and antipyretic activity. Hence, it was decided to study the antiallergic activity of ethanolic extract of S. trifasciata (EEST) on various animal models as well as in vitro conditions, and also to understand possible mechanism of action. Materials and methodsEthanolic extract of S. trifasciata leaves (EEST) were prepared by cold maceration followed by concentration and evaporation under reduced pressure on a rotary evaporator to obtain semisolid mass. The various phytoconstituents were analyzed. The acute toxicity study of EEST was carried out in mice. The antiallergic and anaphylactic activities were evaluated using animal models viz. milk induced eosinophilia and leukocytosis, compound 48/80 induced mast cell degranulation, active and passive cutaneous anaphylaxis and histamine induced pedal edema. In addition, EEST effect on Shultz–Dale reaction in sensitized guinea pig ileum in ex vivo and antioxidant activity by free radical scavenging by DPPH method (in vitro) were also studied. ResultsEEST treatment at 100mg/kg and 200mg/kg p.o inhibited (a) milk-induced increased eosinophilia, leukocytosis, monocytes and neutrophils. (b) Prevented passive cutaneous and active anaphylactoid reactions. (c) Prevented compound 48/80 induced degranulation of sensitized mesenteric mast cells. (d) Inhibited histamine induced pedal edema formation significantly. EEST pretreatment inhibited Shultz–Dale reaction in guinea pig ileum and also elicited potent antioxidant activity. ConclusionExperimental findings demonstrate promising antiallergic and anti-anaphylactic activity of EEST and also elicited potent antioxidant activity. The antiallergic and anti-anphylactic activity might be due to inhibition of release of chemical mediators from mast cells largely by phytoconstituents like steroidal saponins, triterpenoids and flavonoids present in EEST.

Inhibitory effects of adlay bran (Coix lachryma-jobi L. var. ma-yuen Stapf) on chemical mediator release and cytokine production in rat basophilic leukemia cells

Ethnopharmacological relevanceAdlay (Job's tears, Coix lachryma-jobi L. var. ma-yuen Stapf) has long been used in China to treat rheumatism. Aim of the studyWe investigated the anti-allergic effects of adlay bran on rat basophilic leukemia (RBL)-2H3 cells. Materials and methodsTo evaluate the anti-allergic effects of adlay bran, the release of histamines and cytokines were measured using ELISA. To explore the mechanism of these effects, the protein expression levels were determined using western blotting. ResultsA 40.8μg/mL concentration of the ethyl acetate fraction of the ethanolic extracts of adlay bran (ABE-EtOAc) effectively inhibited mast cell degranulation. The 40–100% EtOAc/Hex subfractions of ABE-EtOAc inhibited histamine release with an IC50 of 71–87μg/mL. Moreover, the ABE-EtOAc subfractions suppressed the secretion of interleukin (IL)-4, IL-6 and tumor necrosis factor-α in the RBL-2H3 cells, indicating that adlay bran can inhibit cytokine secretion in the late phase of the allergic reaction. In addition, adlay bran reduced the intracellular production of reactive oxygen species, inhibited the phosphorylation of Akt and decreased the expression of protein kinase C. Furthermore, six phenolic acids and one flavone were isolated. Of these compounds, luteolin showed the most potent inhibitory activity (IC50=1.5μg/mL). ConclusionAdlay bran extract reduced the release of histamines and cytokines and suppressed the production of Akt. These combined effects influenced the signal transduction in RBL-2H3 cells, thereby revealing the mechanisms of the anti-allergic effects of adlay.

Inhibitory Effects of Wasabi Isothiocyanates on Chemical Mediator Release in RBL-2H3 Rat Basophilic Leukemia Cells

Wasabi is a plant of Japanese origin. It belongs to the family Brassicaceae and produces various isothiocyanates (ITCs). To clarify the type I allergies inhibited by wasabi ITCs, we investigated the inhibitory effect on chemical mediator release from dinitrophenylated bovine serum albumin (DNP-BSA)-stimulated RBL-2H3 rat basophilic leukemia cells. Allyl ITC (AITC), sec-butyl ITC (s-BuITC), and 3-butenyl ITC (3-BuITC), which have 3 or 4 carbon chains, inhibited histamine release but did not inhibit the release of leukotriene B4 (LTB4) or cysteinyl LTs (CysLTs). 4-Pentenyl ITC (4-PeITC) and 5-hexenyl ITC (5-HeITC), which have 5 or 6 carbon chains and an unsaturated bond at the end, inhibited LTB4 release but did not inhibit the release of histamine or CysLTs. 6-Methylthiohexyl ITC (6-MTITC), 6-methylsulfinylhexyl ITC (6-MSITC), and 6-methylsulfonylhexyl ITC (6-MSFITC), which have a sulfur atom inserted at the end of a 6-carbon chain, inhibited the release of histamine, LTB4, and CysLTs and the elevation in intracellular Ca(2+). These results suggest that wasabi ITCs inhibited type I allergies by inhibiting chemical mediator release and that the inhibitory effects on each chemical mediator were due to differences in the side chain structure of the wasabi ITCs.

Computational Modeling of Glycolipid-Glycoprotein Complexes: Methods and Applications

The human innate immune response to a Gram-negative bacterial infection involves detection of lipopolysaccharides (LPS), also known as endotoxins, which comprise the bacterial outer cell wall. Distinct from mammalian glycolipid structures, LPS have a conserved chemical pattern that is recognized by the pattern recognition receptor complex formed by myeloid differentiation protein 2 (MD-2) and toll-like receptor 4 (TLR4). While there is a clear correlation between endotoxin acylation and elicited agonist or antagonist responses, the 3D structural basis of this relationship remains unclear and difficult to characterize experimentally. In order to explore, at atomic-resolution, the effects of a range of chemically distinct endotoxins on the structure and dynamics of their MD-2·endotoxin complexes, a series of variably acylated lipid A molecules from E. coli and N. meningitidis in complex with human MD-2 were examined. This included the development and validation of appropriate molecular dynamics force fields to study complex (lipid, carbohydrate and protein) systems. Through these computational developments, in concert with experimental data, specific structural and dynamic features that control dimerization of TLR4 molecules were identified. As dimerization is central to the release of downstream chemical mediators, the results provide a structural foundation for the ability of endotoxins to act as either agonists or antagonists of the TLR4 pathway. Additionally, methods for biologically-relevant characterization of dynamic glycolipid-glycoprotein systems will be discussed.

From agonist to antagonist: Structure and dynamics of innate immune glycoprotein MD-2 upon recognition of variably acylated bacterial endotoxins

The human immune response to an infection by Gram-negative bacteria involves detection of lipopolysaccharides (LPS), also known as endotoxins, which comprise the bacterial outer cell wall. Distinct from mammalian glycolipid structures, LPS have a conserved chemical pattern that is recognized by the pattern recognition receptor complex formed by myeloid differentiation protein 2 (MD-2) and toll-like receptor 4 (TLR4). A remarkable immune-mediated structure-toxicity relationship has been defined that relates to the number of acyl chains in the endotoxin. While there is a clear correlation between endotoxin acylation and elicited agonist or antagonist responses, the 3D structural basis of this relationship remains unclear. In order to explore, at atomic-resolution, the effects of a range of chemically distinct endotoxins on the structure and dynamics of their MD-2·endotoxin complexes, we examined a series of variably acylated lipid A molecules from Escherichia coli and Neisseria meningitidis in complex with human MD-2. Through the application of molecular dynamics simulations, in concert with experimental data, we have identified specific structural and dynamic features of the MD-2-endotoxin complexes that may control dimerization of TLR4 molecules. As dimerization is central to the release of downstream chemical mediators, the results provide a structural foundation for the ability of endotoxins to act as either agonists or antagonists of the TLR4 pathway.

Psychological stress accelerates the onset of tumour formation and alters the type and location of tumours in a DMBA mouse carcinogenesis model

AbstractPsychological stress is recognized as a factor that contributes to increased susceptibility to a number of diseases, including cancer. Psychological stress, via release of chemical mediators, can induce long‐term changes in the organism resulting in an altered responsiveness of the organism to external carcinogens. The present investigation sought to evaluate the impact of stress on polycyclic aromatic hydrocarbon (PAH)‐induced carcinogenesis. We utilized a repetitive restraint stress mouse model and the model PAH, 7,12‐dimethylbenz[a]anthracene (DMBA). Restraint stress was applied three times a week for 6 weeks and DMBA was administered intra‐gastrically once a week for 6 weeks and formation of skin, mammary and ovarian tumours was examined at 26 weeks by pathological analyses. The results indicate that stress accelerates the onset of tumour formation produced in response to DMBA and significantly influences the type and location of tumours. Taken together, these results demonstrate that stress enhances the carcinogenicity of DMBA. These results clearly indicate the need for further characterization of the impact of stress on carcinogen metabolism in oncology. Copyright © 2010 John Wiley & Sons, Ltd.

Rheumatoid Arthritis: Immune Surveillance Gone Wild?

IMMUNE-MEDIATED inflammatory diseases (IMIDs) are a classification of disorders that are caused by abnormal immune function and dysregulation of cytokine pathways that result in systemic disease (Table 1). Although the presenting symptoms of IMIDs can be diverse, they have common characteristics, including a genetic link with an increased incidence in susceptible families, similar environmental triggers, and the activation of pathways and the release of chemical mediators that lead to chronic inflammation.

Isolation of 5-(Hydroxymethyl)Furfural fromLycium chinenseand its Inhibitory Effect on the Chemical Mediator Release by Basophilic Cells

The effect of hot water extracts of LYCIUM CHINENSE fruits (LCF) on the β-hexosaminidase (β-hexo) release by IgE sensitized BSA stimulated rat basophilic leukemia (RBL-2H3) cells was investigated. The ethylacetate (EtOAc) layer of the extract has shown an inhibitory effect on β-hexo release from RBL-2H3 cells at the antigen antibody binding stage. The water (H₂O) fraction (EFW) of the chloroform (CHCl₃) extract from the EtOAc layer also inhibited β-hexo release at the same stage in a dose-dependent manner. With column chromatography preparation, proton and carbon nuclear magnetic resonance (¹H and ¹³C NMR) spectra, electron ionization mass spectrometer (EI-MS) spectra, and high-performance liquid chromatography (HPLC) analysis, the active component was determined to be 5-(hydroxymethyl)furfural (5-HMF). Thus, the 5-HMF showed an inhibitory effect on β-hexo release at the antigen-antibody binding stage and the antibody-receptor binding stage. Furthermore, 5-HMF suppressed [Ca²+] I influx in the IgE-sensitized BSA-stimulated RBL-2H3 cells. Our results show that 5-HMF may be useful for the treatment or prevention of type I allergic diseases.

Diphenyl difluoroketone (EF-24) modulates dendritic cell responses. (101.30)

Abstract Dendritic cells (DCs) are the most potent antigen-presenting cells that link the antigen-specific innate host responses with adaptive immunity. They recognize pathogens, pathogen-ligands and inflammatory signals via pattern recognition receptors. Inflammatory signals induce DC maturation and release of cytokines, chemokines and chemical mediators. We synthesized EF24, a known more potent analog of curcumin, and studied its immunomodulatory properties using immortalized murine DCs (JAWS II). We hypothesized that pharmacological downregulation of proinflammatory pathway by EF24 may suppress lipopolysaccharide (LPS)-induced phenotypic and functional changes in DCs. Murine bone marrow-derived JAWSII DCs were incubated with 1-10 µM EF24 with or without LPS (100 ng/ml). We investigated cell viability, morphology, expression of DC-specific markers and TLR4, NF-κB activity and cytokines. The short- and long-term treatment with EF24 suppressed the LPS-induced expression of DC-markers (CD80, CD86, MHC class II). Immunohistochemical expression of TLR4 in the cells was significantly reduced. Electrophoretic-mobility shift assay showed inhibition of LPS-induced NF-κB activation. EF24 also reduced the expression of IL-6, TNF-α and MCP-1 in DCs. There was no effect of EF24 on viability of DCs in the concentrations used. Overall, our results suggest that the immunomodulatory properties of EF24 may be of therapeutic value in inflammatory conditions, such as septic shock.

Inhibitory Effect of Acteoside Isolated fromCistanche tubulosaon Chemical Mediator Release and Inflammatory Cytokine Production by RBL-2H3 and KU812 Cells

The immediate-type allergic reaction is involved in many allergic diseases such as asthma, allergic rhinitis, and sinusitis. In this study, we investigated the effect of acteoside extracted from CISTANCHE TUBULOSA (Schrenk) R. Wight on the basophilic cell-mediated allergic reaction. The effect of acteoside on β-hexosaminidase release and intracellular [Ca (2+)] I level from rat basophilic leukemia (RBL-2H3) cells was determined. Also, ELISA was used to determine the level of histamine, tumor necrosis factor (TNF)- α, and interleukin (IL)-4 on human basophilic (KU812) cells. The effect of acteoside on basophilic cell viability was determined using the 3-[4,5-dimethylthiazolyl]-2,5-diphenyltetrazolium bromide (MTT) assay. These results indicated that 0.1-10.0 µg/mL acteoside inhibits the release of β-hexosaminidase and [Ca (2+)] I influx from IgE-mediated RBL-2H3 cells. Moreover, acteoside inhibited histamine release, TNF- α, and IL-4 production in a dose-dependent manner from calcium ionophore A23187 plus phorbol 12-myristate 13-acetate (PMA) or compound 48/80-stimulated KU812 cells. Our findings provide evidence that acteoside inhibits basophilic cell-derived immediate-type and delayed-type allergic reactions. This is the first report describing antiallergic activity of acteoside extracted from CISTANCHE TUBULOSA on basophilic cells.

Clinicopathological findings in 5 patients with acute eosinophilic pneumonia

We studied 5 patients with acute eosinophilic pneumonia. Radiologic findings were Kerley's lines and pleural effusion on chest X-ray films, and interlobular septa on chest CT scans. Examination of transbronchial lung biopsy specimens revealed infiltration of eosinophils and lymphocytes into alveolar walls and edema of alveolar walls, interlobular septa, and perivascular connective tissue. The findings of interstitial edema were consistent with the radiological findings. Epithelial damage and bud-type intraluminal fibrosis were also seen, but residual alveolar structure was maintained. Bronchoalveolar lavage fluid contained abnormally high percentages of eosinophils and lympocytes. It also contained basophils and mast cells, which were not seen in fluid from normal subjects. Fluid from patients with chronic eosinophilic pneumonia had significantly fewer basophils than did fluid from those with acute eosinophilic pneumonia (p < 0.01). These findings suggest that release of chemical mediators from basophils plays a key role in interstitial edema in acute eosinophilic pneumonia.

The effect of vagus nerve stimulation and various drugs on chemical mediator release in anesthetized dogs

The effect of vagus nerve stimulation and various drugs on chemical mediator release in anesthetized dogs

The influence of repirinast, an anti-allergic drug, on theophylline pharmacokinetics in patients with bronchial asthma

In order to clarify whether repirinast, an inhibitor of chemical mediator release, could influence the pharmacokinetics of theophylline, a loading test using intravenous injection of aminophylline was performed in 10 subjects with bronchial asthma before and after treatment with 300 mg/day of repirinast. There was no significant difference in theophylline half-life before treatment (7.25 +/- 2.43 hr) and after treatment (7.82 +/- 3.35 hr). There was no significant difference in theophylline clearance before treatment (0.047 +/- 0.018 L/kg/hr) and after treatment (0.047 +/- 0.020 L/kg/hr). These results demonstrated that repirinast does not modify theophylline pharmacokinetics significantly.

Effect of tranilast on matrix metalloproteinase production from neutrophils in-vitro

Tranilast is an anti-allergic agent that blocks the release of chemical mediators, such as histamine and leukotrienes from mast cells, and has been reported to suppress keloid and hypertrophic scar formation. Since matrix metalloproteinases (MMPs) play an essential role in tissue remodelling, this study was undertaken to determine whether tranilast suppresses MMP production from neutrophils after lipopolysaccharide (LPS) stimulation in-vitro. Neutrophils from five healthy donors (1 x 10(5) cells/mL) were stimulated with 1.0 microg mL(-1) LPS in the presence or absence of various concentrations of tranilast for 24 h. MMP-7, MMP-8, MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 levels in the culture supernatants were assayed by ELISA. In addition, the influence of tranilast on MMP mRNA expression and transcriptional factor activation in cells cultured for 12 h and 4 h was also evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Tranilast inhibited MMP and TIMP-1 production from neutrophils when cells were treated with the agent at more than 5.0 x 10(-5) M. It also suppressed MMP mRNA expression and transcriptional factor activation induced in neutrophils by LPS stimulation. The results suggest that tranilast inhibits the formation of keloid scarring through the suppression of factors such as MMPs and TIMP, which are essential for tissue remodelling, from inflammatory cells.

Inhibitory effects of diterpene acids from root of Aralia cordata on IgE-mediated asthma in guinea pigs

This study evaluated the anti-asthmatic activities of four diterpene acids isolated from Aralia cordata root that are proposed to be the active ingredients in its traditional use as a treatment for inflammation, overheating, pain and spasm in Korea. The diterpene acids were identified as kaurenoic acid, 7-oxo-sandaracopimaric acid, 17-hydroxy-ent-kaur-15-en-19-oic acid, and hederagenin, by comparing their phytochemical and spectroscopic data with previous reports. The effects of diterpene acids on asthma were evaluated by determining the specific airway resistance (sRaw) during the immediate asthmatic response (IAR) and the late-phase asthmatic response (LAR) in guinea pigs with IgE-mediated asthma. Recruitment of leukocytes and the presence of chemical mediators in bronchoalveolar lavage fluid (BALF) were determined, and histopathological surveys performed. The four diterpene acids dosed at 25∼100 mg/kg had dose-dependently anti-asthmatic effects: 7-oxo-sandaracopimaric acid > 17-hydroxy-ent-kaur-15-en-19-oic acid > kaurenoic acid > hederagenin. 7-oxo-sandaracopimaric acid (25 mg/kg) significantly ( p < 0.05) inhibited sRaw by 59.5% in IAR and LAR, and also dose-dependently inhibited recruitment of eosinophils and neutrophils into lung and release of chemical mediators, histamine, and the activity of phospholipase A 2 and eosinophil peroxidase in BALF. 7-Oxo-sandaracopimaric acid had the highest activity among the diterpene acids. But its effect was lower than cromolyn sodium, salbutamol, or dexamethasone in both the IAR and the LAR. These results suggested that C 7-oxo radical of 7-oxo-sandaracopimaric acid was more active than the C 7-hydroxy and hydrogen of the other compounds, and showed diterpene acids have anti-asthmatic effects, supporting the traditional application of this herb in treating IgE-mediated asthma.

Manejo analgésico y anestésico en la mastocitosis sistémica: a propósito de un caso

Mastocytoses are a heterogeneous group of entities characterized by mast cell proliferation in one or more organs or tissues. When tissues other than the skin are involved, the disease is called systemic mastocytosis (SM). SM is a highly infrequent disease, whose incidence and prevalence are unknown. The anesthetic management of these patients must consider the fact that many drugs can trigger massive release of chemical mediators of mast cells. We report the case of a patient diagnosed with SM who underwent total hysterectomy and discuss the importance of thorough preoperative study, as well as the anesthetic technique and type of analgesia chosen. We also report our protocol for anesthetic management in this disease.

Investing Early Signaling Events in IgE-FcɛRI Activation Using SEM

Antigen-mediated cross-linking of immunoglobulin E (IgE) bound to its high affinity receptor FcɛRI on mast cells initiates a transmembrane signaling cascade that results in cell activation and exocytotic release of chemical mediators involved in allergic response. Plasma membrane lipids and proteins redistribute as part of this transmembrane signaling process. To understand the functional role of these redistributions, resolution of their size, composition and structure on the nanometer scale is required. We utilize high resolution scanning electron microscopy (SEM) to directly visualize sub-micron membrane domains in intact cell membranes. In our experiments, the distribution of gold-labeled proteins and lipids is analyzed at the surface of intact fixed cells using backscattered electron detection. In parallel, we also observe membrane topography using secondary electron detection. We use a pair-correlation function analysis to quantify protein distributions and parameterized domain size. We have mapped the distribution of a variety of proteins, both related and non-related to the IgE signaling pathway. Using this experimental and quantitative method, we observe dramatic changes in the nano-scale membrane distribution of IgE due to stimulation with multivalent ligands. In resting cells, IgE receptors are clustered into small domains less than 30nm. After stimulation, receptors redistribute into large domains that are correlated at long length-scales and subsequently reduce in size at long stimulation times. We also observe cross-linking-dependent rearrangement of several inner leaflet-associated proteins implicated in early signaling events. In contrast, outer leaflet GPI-anchored proteins are not affected. We have also quantified the co-redistribution of IgE with other membrane proteins after stimulation using cross-correlation functions. These findings provide valuable insights into the mechanisms that drive the selective nanoscopic reorganization of plasma membrane proteins during immune cell signaling.

Effect of 2,3,7,8-tetrachlorodibenzo- p-dioxin on scratching behavior in mice

The present study was performed to study the effect of 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) on scratching behavior in hairless mice, which are highly sensitive to pruritogens (mediators causing itching), except for histamine, and are suitable for time-course studies due to their hairless skin. TCDD is a well-known environmental pollutant that causes skin diseases with itching; therefore, we examined whether TCDD induced itching. Oral administration of TCDD caused no increase in scratching behavior when used alone, whereas TCDD in combination with distilled water or acetone/olive oil application caused a significant increase in scratching behavior. Furthermore, nerve growth factor (NGF) content in the skin increased significantly. A single administration of chlorpheniramine (histamine H1 receptor antagonist), tranilast (chemical mediator release inhibitor) and olopatadine (histamine H1 receptor antagonist) had no effect on scratching behavior induced by TCDD in combination with acetone/olive oil application. With repeated administration for 7 days, chlorpheniramine and tranilast had no effect on scratching behavior, whereas olopatadine significantly inhibited scratching behavior. In addition, only olopatadine significantly inhibited NGF content in the skin. From these findings, it can be concluded that TCDD is not a pruritogen but causes alloknesis (itchy skin) with the simultaneous use of trivial external stimulation. In addition, it was found that drugs which decreased skin NGF contents may inhibit this scratching behavior.

FcepsilonRI-alpha siRNA inhibits the antigen-induced activation of mast cells.

FcepsilonRI, The high affinity receptor for IgE plays a critical role in triggering the allergic reactions. It is responsible for inducing mast cell degranulation and deliberation of allergy mediators when it is aggregated by allergen and IgE complexes. FcepsilonRI on the mast cells consists of three subunits; alpha chain directly binds IgE, beta chain and dimmer of gamma chains together mediate intracellular signaling. Cross-linking of IgE-bound FcepsilonRI on the surface of mast cells and basophils by the multivalent antigen induces release of chemical mediators. The present in vitro study was designed to investigate the effect of synthetic FcepsilonRI-alpha siRNA on the antigen-induced activation of MC/9 cells. MC/9 cells which are murine mast cells were transfected by FcepsilonRI-alpha siRNA and negative control siRNA. After 6 h, anti-DNP (Dinitrophenyl) IgE was used for the cells sensitization. Then the cells were challenged with Dinitrophenyl-Human Serum Albumin (DNP-HSA) for mast cell degranulation induction before collection of supernatants. The amount of mRNA and protein expression was measured by Real Time PCR and western blot analysis, respectively. Determination of the expression rate of FcepsilonRI-alpha on cell surface was achieved by flow cytometry. ELISA and spectrophotometry methods were used subsequently for measuring the effects of FcepsilonRI-alpha siRNA on antigen-induced histamine and beta-hexosaminidase release. FcepsilonRI-alpha siRNA treated cells showed significant decrease in FcepsilonRI-alpha mRNA and protein expression in comparison to control cells. FcepsilonRI-mediated mast cell release of beta-hexosaminidase and histamine were also inhibited. In this study it was shown that FcepsilonRI-alpha siRNA could suppress FcepsilonRI-alpha expression and inhibited degranulation and histamine release in antigen-stimulated MC/9 cells. In conclusion, knock-down of FcepsilonRI-alpha by siRNA could be a promising method for inhibition of the mast cell-mediated allergic reactions.

Role of the bladder urothelium in voiding dysfunction

The urothelium is a highly effective constant permeability barrier that protects the blood from toxic urinary substances. However, a large and growing body of evidence supports additional roles for the urothelium, including sensory and transduction/signaling roles that enable responses to chemical or mechanical stimuli. Reciprocal communication between urothelial cells with closely located bladder nerves and other cell types, including detrusor smooth muscle and interstitial cells, is likely. Diseases affecting the urinary bladder may affect urothelial receptor channel expression and release of chemical mediators. Urothelial neuropeptide receptor, chemokine receptor, and neurotrophin receptor expression, transduction/signaling, and modulation in animal models of urinary bladder inflammation and human studies of bladder dysfunction are presented. Substrates underlying micturition reflex plasticity induced by urinary bladder disease/dysfunction are likely to include bladder primary afferent cells, lumbosacral spinal cord, and the urothelium.