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Shuba YM. Beyond Neuronal Heat Sensing: Diversity of TRPV1 Heat-Capsaicin Receptor-Channel Functions. Front Cell Neurosci 2021; 14:612480. [PMID: 33613196 PMCID: PMC7892457 DOI: 10.3389/fncel.2020.612480] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/23/2020] [Indexed: 12/20/2022] Open
Abstract
Transient receptor potential vanilloid 1 (TRPV1) is a calcium-permeable ion channel best known for its ability to be gated by the pungent constituent of red chili pepper, capsaicin, and related chemicals from the group of vanilloids as well as by noxious heat. As such, it is mostly expressed in sensory neurons to act as a detector of painful stimuli produced by pungent chemicals and high temperatures. Its activation is also sensitized by the numerous endogenous inflammatory mediators and second messengers, making it an important determinant of nociceptive signaling. Except for such signaling, though, neuronal TRPV1 activation may influence various organ functions by promoting the release of bioactive neuropeptides from sensory fiber innervation organs. However, TRPV1 is also found outside the sensory nervous system in which its activation and function is not that straightforward. Thus, TRPV1 expression is detected in skeletal muscle; in some types of smooth muscle; in epithelial and immune cells; and in adipocytes, where it can be activated by the combination of dietary vanilloids, endovanilloids, and pro-inflammatory factors while the intracellular calcium signaling that this initiates can regulate processes as diverse as muscle constriction, cell differentiation, and carcinogenesis. The purpose of the present review is to provide a clear-cut distinction between neurogenic TRPV1 effects in various tissues consequent to its activation in sensory nerve endings and non-neurogenic TRPV1 effects due to its expression in cell types other than sensory neurons.
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Affiliation(s)
- Yaroslav M Shuba
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
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2
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Toktanis G, Kaya-Sezginer E, Yilmaz-Oral D, Gur S. Potential therapeutic value of transient receptor potential channels in male urogenital system. Pflugers Arch 2018; 470:1583-1596. [PMID: 30194638 DOI: 10.1007/s00424-018-2188-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/11/2018] [Accepted: 07/24/2018] [Indexed: 12/11/2022]
Abstract
Transient receptor potential (TRP) channels comprise a family of cation channels implicated in a variety of cellular processes including light, mechanical or chemical stimuli, temperature, pH, or osmolarity. TRP channel proteins are a diverse family of proteins that are expressed in many tissues. We debated our recent knowledge about the expression, function, and regulation of TRP channels in the different parts of the male urogenital system in health and disease. Emerging evidence suggests that dysfunction of TRP channels significantly contributes to the pathophysiology of urogenital diseases. So far, there are many efforts underway to determine if these channels can be used as drug targets to reverse declines in male urogenital function. Furthermore, developing safe and efficacious TRP channel modulators is warranted for male urogenital disorders in a clinical setting.
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Affiliation(s)
| | - Ecem Kaya-Sezginer
- Faculty of Pharmacy, Department of Biochemistry and Pharmacology, Ankara University, Tandogan, 06100, Ankara, Turkey
| | - Didem Yilmaz-Oral
- Faculty of Pharmacy, Department of Biochemistry and Pharmacology, Ankara University, Tandogan, 06100, Ankara, Turkey.,Faculty of Pharmacy, Department of Pharmacology, Cukurova University, Adana, Turkey
| | - Serap Gur
- Faculty of Pharmacy, Department of Biochemistry and Pharmacology, Ankara University, Tandogan, 06100, Ankara, Turkey.
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3
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Birder LA, Kullmann FA. Role of neurogenic inflammation in local communication in the visceral mucosa. Semin Immunopathol 2018; 40:261-279. [PMID: 29582112 PMCID: PMC5960632 DOI: 10.1007/s00281-018-0674-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/06/2018] [Indexed: 12/27/2022]
Abstract
Intense research has focused on the involvement of the nervous system in regard to cellular mechanisms underlying neurogenic inflammation in the pelvic viscera. Evidence supports the neural release of inflammatory factors, trophic factors, and neuropeptides in the initiation of inflammation. However, more recently, non-neuronal cells including epithelia, endothelial, mast cells, and paraneurons are likely important participants in nervous system functions. For example, the urinary bladder urothelial cells are emerging as key elements in the detection and transmission of both physiological and nociceptive stimuli in the lower urinary tract. There is mounting evidence that these cells are involved in sensory mechanisms and can release mediators. Further, localization of afferent nerves next to the urothelium suggests these cells may be targets for transmitters released from bladder nerves and that chemicals released by urothelial cells may alter afferent excitability. Modifications of this type of communication in a number of pathological conditions can result in altered release of epithelial-derived mediators, which can activate local sensory nerves. Taken together, these and other findings highlighted in this review suggest that neurogenic inflammation involves complex anatomical and physiological interactions among a number of cell types in the bladder wall. The specific factors and pathways that mediate inflammatory responses in both acute and chronic conditions are not well understood and need to be further examined. Elucidation of mechanisms impacting on these pathways may provide insights into the pathology of various types of disorders involving the pelvic viscera.
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Affiliation(s)
- Lori A Birder
- Department of Medicine, University of Pittsburgh School of Medicine, A 1217 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA, 15261, USA.
- Department of Chemical Biology and Pharmacology, University of Pittsburgh School of Medicine, A 1217 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA, 15261, USA.
| | - F Aura Kullmann
- Department of Medicine, University of Pittsburgh School of Medicine, A 1217 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA, 15261, USA
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4
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Cordero K, Coronel GG, Serrano-Illán M, Cruz-Bracero J, Figueroa JD, De León M. Effects of Dietary Vitamin E Supplementation in Bladder Function and Spasticity during Spinal Cord Injury. Brain Sci 2018; 8:E38. [PMID: 29495419 PMCID: PMC5870356 DOI: 10.3390/brainsci8030038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 11/25/2022] Open
Abstract
Traumatic spinal cord injury (SCI) results in debilitating autonomic dysfunctions, paralysis and significant sensorimotor impairments. A key component of SCI is the generation of free radicals that contributes to the high levels of oxidative stress observed. This study investigates whether dietary supplementation with the antioxidant vitamin E (alpha-tocopherol) improves functional recovery after SCI. Female adult Sprague-Dawley rats were fed either with a normal diet or a dietary regiment supplemented with vitamin E (51 IU/g) for eight weeks. The rats were subsequently exposed either to a contusive SCI or sham operation, and evaluated using standard functional behavior analysis. We report that the rats that consumed the vitamin E-enriched diet showed an accelerated bladder recovery and significant improvements in locomotor function relative to controls, as determined by residual volumes and Basso, Beatie, and Bresnaham BBB scores, respectively. Interestingly, the prophylactic dietary intervention did not preserve neurons in the ventral horn of injured rats, but it significantly increased the numbers of oligodendrocytes. Vitamin E supplementation attenuated the depression of the H-reflex (a typical functional consequence of SCI) while increasing the levels of supraspinal serotonin immunoreactivity. Our findings support the potential complementary use of vitamin E to ameliorate sensory and autonomic dysfunctions associated with spinal cord injury, and identified promising new cellular and functional targets of its neuroprotective effects.
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Affiliation(s)
- Kathia Cordero
- Center for Health Disparities and Molecular Medicine, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
| | - Gemma G Coronel
- Center for Health Disparities and Molecular Medicine, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
| | - Miguel Serrano-Illán
- Center for Health Disparities and Molecular Medicine, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
| | - Jennifer Cruz-Bracero
- Center for Health Disparities and Molecular Medicine, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
| | - Johnny D Figueroa
- Center for Health Disparities and Molecular Medicine, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
| | - Marino De León
- Center for Health Disparities and Molecular Medicine, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
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5
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Franken J, Uvin P, De Ridder D, Voets T. TRP channels in lower urinary tract dysfunction. Br J Pharmacol 2014; 171:2537-51. [PMID: 24895732 PMCID: PMC4008998 DOI: 10.1111/bph.12502] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/17/2013] [Accepted: 10/20/2013] [Indexed: 12/13/2022] Open
Abstract
Lower urinary tract dysfunction (LUTd) represents a major healthcare problem. Although it is mostly not lethal, associated social disturbance, medical costs, loss of productivity and especially diminished quality of life should not be underestimated. Although more than 15% of people suffer from a form of LUTd to some extent, pathophysiology often remains obscure. In the past 20 years, transient receptor potential (TRP) channels have become increasingly important in this field of research. These intriguing ion channels are believed to be the main molecular sensors that generate bladder sensation. Therefore, they are intensely pursued as new drug targets for both curative and symptomatic treatment of different forms of LUTd. TRPV1 was the first of its class to be investigated. Actually, even before this channel was cloned, it had already been targeted in the bladder, with clinical trials of intravesical capsaicin instillations. Several other polymodally gated TRP channels, particularly TRPM8, TRPA1 and TRPV4, also appear to play a prominent role in bladder (patho)physiology. With this review, we provide a brief overview of current knowledge on the role of these TRP channels in LUTd and their potential as molecular targets for treatment.
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Affiliation(s)
- J Franken
- Laboratory of Experimental Urology, KU LeuvenLeuven, Belgium
| | - P Uvin
- Laboratory of Experimental Urology, KU LeuvenLeuven, Belgium
| | - D De Ridder
- Laboratory of Experimental Urology, KU LeuvenLeuven, Belgium
| | - T Voets
- Laboratory of Ion Channel Research, KU LeuvenLeuven, Belgium
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Randviir EP, Metters JP, Stainton J, Banks CE. Electrochemical impedance spectroscopy versus cyclic voltammetry for the electroanalytical sensing of capsaicin utilising screen printed carbon nanotube electrodes. Analyst 2013; 138:2970-81. [PMID: 23539507 DOI: 10.1039/c3an00368j] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Screen printed carbon nanotube electrodes (SPEs) are explored as electroanalytical sensing platforms for the detection of capsaicin in both synthetic capsaicin solutions and capsaicin extracted from chillies and chilli sauces utilising both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that the technique which is most applicable to the electroanalytical detection of capsaicin depends upon the analyte concentration: for the case of low capsaicin concentrations, CV is a more appropriate method as capsaicin exhibits characteristic voltammetric waves of peak heights relevant to the capsaicin concentration; but for the case of high capsaicin concentrations where the voltammetric waves merge and migrate out of the potential window, EIS is shown to be a more appropriate technique, owing to the observed linear increases in R(ct) with increasing concentration. Furthermore, we explore different types of screen printed carbon nanotube electrodes, namely single- and multi- walled carbon nanotubes, finding that they are technique-specific: for the case of low capsaicin concentrations, single-walled carbon nanotube SPEs are preferable (SW-SPE); yet for the case of EIS at high capsaicin concentrations, multi-walled carbon nanotube SPEs (MW-SPE) are preferred, based upon analytical responses. The analytical performance of CV and EIS is applied to the sensing of capsaicin in grown chillies and chilli sauces and is critically compared to 'gold standard' HPLC analysis.
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Affiliation(s)
- Edward P Randviir
- Faculty of Science and Engineering, School of Chemistry and the Environment, Division of Chemistry and Environmental Science, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, Lancs, UK
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Philyppov IB, Paduraru ON, Andreev YA, Grishin EV, Shuba YM. Modulation of TRPV1-dependent contractility of normal and diabetic bladder smooth muscle by analgesic toxins from sea anemone Heteractis crispa. Life Sci 2012; 91:912-20. [PMID: 22982418 DOI: 10.1016/j.lfs.2012.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/17/2012] [Accepted: 09/04/2012] [Indexed: 01/27/2023]
Abstract
AIMS TRPV1-expressing, capsaicin (CAP)-sensitive afferent fibers innervating bladder in addition to sensory function also exhibit "efferent" features consisting in TRPV1-dependent release of tachykinins (TAC) affecting detrusor smooth muscle (DSM) contractions. Our aim was to investigate the effects of two novel polypeptide inhibitors of TRPV1 from the venom of tropical sea anemone Heteractis crispa, APHC1 and APHC3, on the contractions of DSM from bladders of normal and diabetic rats. MAIN METHODS Experiments were conducted on urothelium-devoid DSM strips from normal rats and rats 8weeks after streptozotocin-induced diabetes by means of contraction force measurements. KEY FINDINGS Pre-exposure of DSM strips to APHC1 or APHC3 (200nM) specifically inhibited CAP-induced, TRPV1-dependent contractions. Both peptides also transiently enhanced basal tone and spontaneous contractions of DSM strips followed by delayed suppression of electric field stimulation (EFS)-evoked nonadrenergic-noncholinergic (NANC) contractions. The decrease of the amplitude of EFS-evoked NANC contractions by АРНС1 or АРНС3 reached 38.5±3.4% and 25.1±1.6%, respectively, in normal DSM strips and 46.3±3.3% and 43.9±1.8%, respectively, in diabetic ones. APHC-peptide-induced transient enhancement of basal tone could be mimicked by serine protease inhibitor, 4-(2-aminoethyl)bezenesulfonyl fluoride (300 μM). SIGNIFICANCE Our results demonstrate that АРНС1 and АРНС3 may be considered as effective inhibitors of bladder contractility especially during diabetic cystopathy. Modality of action of APHC-polypeptides via the mechanisms involving decreased TRPV1-dependent release of TAC from bladder afferents and suppression of TAC degradation due to their activity as endogenous proteases inhibitors is proposed.
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Affiliation(s)
- Igor B Philyppov
- Bogomoletz Institute of Physiology of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
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8
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Abstract
The members of transient receptor potential (TRP) superfamily of cationic ion channels represent universal sensors, which convert multiple exogenous and endogenous chemical and physical stimuli into electrical and functional cellular responses. TRPs are widely distributed in many different tissues, and expression of numerous TRP types has been reported in lower urinary tract (LUT) tissues, neuronal fibers innervating the bladder and urethra, and epithelial and muscular layers of the bladder and urethral walls, where they are mainly involved in nociception and mechanosensory transduction. As such, they represent attractive targets for treating LUT disorders. Although information on the functional significance of many of the TRP proteins in the LUT remains very limited, compelling evidence has accumulated for a pivotal role of TRPV1, TRPV2, TRPV4, TRPM8, and TRPA1 in normal and pathological LUT function, mainly as sensors of stretch and chemical irritation. Further studies into these and other TRPs in the LUT will facilitate the development of improved therapeutic strategies to target these channels in LUT disorders.
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9
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Malykhina AP. Neural mechanisms of pelvic organ cross-sensitization. Neuroscience 2007; 149:660-72. [PMID: 17920206 DOI: 10.1016/j.neuroscience.2007.07.053] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 07/05/2007] [Accepted: 07/12/2007] [Indexed: 12/12/2022]
Abstract
Clinical observations of viscerovisceral referred pain in patients with gastrointestinal and genitourinary disorders suggest an overlap of neurohumoral mechanisms underlying both bowel and urinary bladder dysfunctions. Close proximity of visceral organs within the abdominal cavity complicates identification of the exact source of chronic pelvic pain, where it originates, and how it relocates with time. Cross-sensitization among pelvic structures may contribute to chronic pelvic pain of unknown etiology and involves convergent neural pathways of noxious stimulus transmission from two or more organs. Convergence of sensory information from discrete pelvic structures occurs at different levels of nervous system hierarchy including dorsal root ganglia, the spinal cord and the brain. The cell bodies of sensory neurons projecting to the colon, urinary bladder and male/female reproductive organs express a wide range of membrane receptors and synthesize many neurotransmitters and regulatory peptides. These substances are released from nerve terminals following enhanced neuronal excitability and may lead to the occurrence of neurogenic inflammation in the pelvis. Multiple factors including inflammation, nerve injury, ischemia, peripheral hyperalgesia, metabolic disorders and other pathological conditions dramatically alter the function of directly affected pelvic structures as well as organs located next to a damaged domain. Defining precise mechanisms of viscerovisceral cross-sensitization would have implications for the development of effective pharmacological therapies for the treatment of functional disorders with chronic pelvic pain such as irritable bowel syndrome and painful bladder syndrome. The complexity of overlapping neural pathways and possible mechanisms underlying pelvic organ crosstalk are analyzed in this review at both systemic and cellular levels.
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Affiliation(s)
- A P Malykhina
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA.
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10
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van Rijswijk JB, Gerth van Wijk R. Capsaicin treatment of idiopathic rhinitis: the new panacea? Curr Allergy Asthma Rep 2006; 6:132-7. [PMID: 16566863 DOI: 10.1007/s11882-006-0051-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The management of patients with perennial nonallergic or idiopathic rhinitis is difficult. Diagnosis and treatment are hampered by several factors. First, the diagnosis is made by exclusion of other nasal diseases. As a consequence, idiopathic rhinitis is not defined according to clear-cut criteria. A commonly accepted phenotype of idiopathic rhinitis does not exist. Second, the pathophysiology of idiopathic rhinitis is not yet fully elucidated. In contrast with allergic rhinitis, inflammation does not appear to play an important role in idiopathic rhinitis. Recent studies indicate a neural dysregulation of the nasal mucosa. Additionally, the available therapeutic arsenal comprising both pharmacotherapy and surgery is at best partially efficacious in these patients. The efficacy of repeated capsaicin application has been established in several randomized controlled trials. This treatment modality may be the first step to more specific and better treatment options for patients with idiopathic rhinitis that is unresponsive to standard treatment.
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11
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Vignes JR, De Seze M, Dobremez E, Joseph PA, Guérin J. Sacral neuromodulation in lower urinary tract dysfunction. Adv Tech Stand Neurosurg 2006; 30:177-224. [PMID: 16350455 DOI: 10.1007/3-211-27208-9_5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Vesico-urethral dysfunction is a major problem in daily medical practice due to its psychological disturbances, its social costs and its high impact on quality of life. Recently, sacral neuromodulation, namely the electrical stimulation of the sacral nerves, appears to have become an alternative for radical bladder surgery particularly in cases of idiopathic bladder overactivity. The mechanism of action is only partially understood but it seems to involve a modulation in the spinal cord due to stimulation of inhibitory interneurons. Temporary sacral nerve stimulation is the first step. It comprises the temporary application of neuromodulation as a diagnostic test to determine the best location for the implant and to control the integrity of the sacral root. If test stimulation is successful, a permanent device is implanted. This procedure is safe in experienced hands. So-called idiopathic bladder overactivity still the major indication for this technique. Patients not likely to benefit from the procedure were those with complete or almost complete spinal lesions, but incomplete spinal lesions seemed to be a potential indication. This technique is now also indicated in the case of idiopathic chronic retention and chronic pelvic pain syndrome. When selection is performed, more than three-quarters of the patients showed a clinically significant response with 50% or more reduction in the frequency of incontinent episodes, but the results vary according to the author's mode of evaluation. From the economic point of view, the initial investment in the device is amortized in the mid-term by savings related to lower urinary tract dysfunction. Finally, this technique requires an attentive follow-up and adjustments to the electric parameters so as to optimize the equilibrium between the neurological systems.
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Affiliation(s)
- J R Vignes
- Department of Neurosurgery, Medical School Hospital, Hôpital Pellegrin, Bordeaux, France
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12
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Chen TYH, Corcos J, Camel M, Ponsot Y, Tu LM. Prospective, randomized, double-blind study of safety and tolerability of intravesical resiniferatoxin (RTX) in interstitial cystitis (IC). Int Urogynecol J 2005; 16:293-7. [PMID: 15818465 DOI: 10.1007/s00192-005-1307-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Accepted: 02/15/2005] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To determine the safety and tolerability of intravesical resiniferatoxin (RTX) in interstitial cystitis (IC) patients. MATERIALS AND METHODS IC patients were instilled with 50 cc of test solution containing either placebo, 0.05 microM or 0.10 microM RTX in the bladder. Plasma concentration of RTX and its degradant resiniferonol 9-, 13-, 14-orthophenylacetate was measured. Immediate post-treatment blood sampling and cystoscopy were performed. Symptoms were evaluated before treatment, at 4- and at 12-week follow-ups, using VAS indicator for pain, voiding diary, and O'Leary's IC symptom/problem indices. RESULTS Among 22 patients observed (ten in 0.10 microM RTX, eight in 0.05 microM RTX, and four in placebo groups), the most commonly reported adverse event was pain during instillation (80.0%, 87.5%, and 25.0%). No serious adverse events were reported. CONCLUSIONS Use of intravesical RTX in IC patients is associated with important tolerability issues but safe at 0.10 microM and 0.05 microM.
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Affiliation(s)
- Tony Y H Chen
- Centre Hospitalier Universitaire de Sherbrooke, Service d'urologie 3001, Canada.
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13
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Bjorling DE, Beckman M, Saban R. Neurogenic inflammation of the bladder. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 539:551-83. [PMID: 15176313 DOI: 10.1007/978-1-4419-8889-8_37] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Current evidence suggests multiple and redundant pathways through which the nervous system can initiate, amplify, and perpetuate inflammation. Many of the processes initiated by neurogenic inflammation have the capacity to recruit the participation of additional sensory nerves. These observations indicate that effective strategies for prevention or treatment of neurogenic inflammation of the bladder will entail or require intervention at multiple points. It has been observed that pain management in the future will be based on selective intervention tailored to the specific processes modulating pain perception in individual patients. It is exciting to contemplate the same approach to prevention and treatment of neurogenic bladder inflammation.
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Affiliation(s)
- Dale E Bjorling
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, USA
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Abstract
The cloned vanilloid (capsaicin) receptor subtype 1 (VR1) integrates multiple noxious stimuli on peripheral terminals of primary sensory neurons. The initial excitation of these neurons is followed by a lasting refractory state, traditionally termed desensitization, that has clear therapeutic potential. Capsaicin is used to relieve neuropathic pain, uremic pruritus, and bladder overactivity. The ultrapotent vanilloid resiniferatoxin, now in phase 2 clinical trials, has improved tolerability. A less recognized human exposure to high capsaicin concentrations may occur by pepper sprays used in law enforcement. Evidence is mounting that VR1 expression is not restricted to sensory neurons. From the olfactory bulb to the cerebellum, VR1-expressing neurons are present in a number of brain nuclei, where they might be activated by anandamide. VR1 presence also was demonstrated in nonneuronal tissues. These discoveries place VR1 in a much broader perspective than pain perception and enhance the potential for unforeseen side effects, especially following prolonged vanilloid therapy. The expression of VR1 is plastic and down-regulated during vanilloid therapy, which might have a pivotal role in desensitization. Good evidence suggests altered VR1 expression in various disease states. This recognition not only may provide novel insights into pathogenesis but also may prove useful in diagnosis.
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Affiliation(s)
- Arpad Szallasi
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Szallasi A, Fowler CJ. After a decade of intravesical vanilloid therapy: still more questions than answers. Lancet Neurol 2002; 1:167-72. [PMID: 12849485 DOI: 10.1016/s1474-4422(02)00072-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Vanilloid sensitivity is a functional signature of a subset of unmyelinated fibres innervating the urinary bladder. The role that these nerves have in the physiological control of storage and voiding is unclear. However, after the bladder has been disconnected by spinal injury from the pontine micturition centre, vanilloid-sensitive fibres assume a central role in the reflex emptying of the bladder that occurs at low volumes. Intravesical vanilloid (capsaicin or resiniferatoxin) administration is beneficial in this disorder by "desensitising" these nerves. Resiniferatoxin is superior to capsaicin in terms of its tolerability profile. Investigators are moving rapidly to identify the mechanisms by which desensitisation to vanilloids occurs. Vanilloids induce lasting, but fully reversible, changes in gene expression, including downregulation of the vanilloid receptor subtype 1. It is hoped that application of gene chip technologies will address the global profile of vanilloid-induced changes in gene expression and their relative contribution to desensitisation. Drugs that target signalling mechanisms that bring about these changes in gene expression have obvious therapeutic potential.
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Affiliation(s)
- Arpad Szallasi
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.
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16
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Abstract
Neurons possessing C-fibers transmit nociceptive information into the central nervous system and participate in various reflex responses. These neurons carry receptors that bind capsaicin, recently identified as the vanilloid VR1 receptor. Excitation of these cells by capsaicin is followed by a lasting refractory state, termed desensitisation, in which the neurons fail to respond to a variety of noxious stimuli. Desensitisation to capsaicin has a clear therapeutic potential in relieving neuropathic pain and ameliorating urinary bladder overactivity, just to cite 2 important examples. Vanilloids may also be beneficial in the treatment of benign prostate hyperplasia (BPH). Since the majority of elderly patients have neuropathic pain co-existent with urinary incontinence and/or BPH, a drug that ameliorates pain and improves urinary symptoms at the same time promises to be of great clinical value in geriatric medicine. In fact, capsaicin has already been shown to have a role in the treatment of conditions that can arise in the elderly, including herpes zoster-related neuropathic pain, diabetic neuropathy, postmastectomy pain, uraemic itching associated with renal failure, and urinary incontinence. The potent VR1 agonist resiniferatoxin, now in phase II clinical trials, appears to be superior to capsaicin in terms of its tolerability profile. Recent discoveries enhance the therapeutic potential of vanilloids. The recognition that VR1 also functions as a principal receptor for protons and eicosanoids implies that VR1 antagonists may be of value in the treatment of inflammatory hyperalgesia and pain. Animal experimentation has already lent support to this assumption. The discovery of VR1-expressing cells in the brain as well as in non-neural tissues such as the kidney and urothelium places VR1 in a much broader perspective than peripheral pain perception, and is hoped to identify further, yet unsuspected, indications for vanilloid therapy. The realisation that VR1 and cannabinoid CB1 receptors have overlapping ligand recognition properties may also have far-reaching implications for vanilloid therapy. In fact, arvanil, a combined agonist of VR1 and CB1 receptors, has already proved to be a powerful analgesic drug in the mouse. From academic molecular biology laboratories to industrial drug discovery centres to the clinics, there is a steady flow of new data, forcing us to constantly revise the ways we are thinking about vanilloid receptor ligands and their hopes and realities for the future. This review covers the most promising current trends in vanilloid research with special emphasis on geriatric medicine.
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Affiliation(s)
- A Szallasi
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, USA.
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Szabo T, Biro T, Gonzalez AF, Palkovits M, Blumberg PM. Pharmacological characterization of vanilloid receptor located in the brain. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2002; 98:51-7. [PMID: 11834295 DOI: 10.1016/s0169-328x(01)00313-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Specific [3H]resiniferatoxin (RTX) binding detects the vanilloid receptor type I (VR1). In the present study we demonstrate specific, high-affinity, saturable [3H]RTX binding in various areas of monkey brain not known to be innervated by primary afferent neurons as well as in spinal cord and dorsal root ganglion neurons of the same origin. Detailed pharmacological characterization and comparison revealed no major difference in binding affinities between the peripheral and the central sites as measured by K(d)/K(i) values. In general, lower receptor density was measured in selected brain areas than in the periphery. Areas with higher receptor density were detected in the locus ceruleus, preoptic area, and medial basal hypothalamus of the brain. Both capsaicin and the competitive antagonist capsazepine inhibited the specific binding of [3H]RTX to membrane preparations of the dorsal horn of the spinal cord and dorsal root ganglia with K(i) values of 4.3+/-0.32 microM and 2.7+/-0.33 microM, respectively. Inhibition was observed in the central areas (hypothalamus) with K(i) values of 0.95+/-0.1 microM for capsaicin and 0.86+/-0.11 microM for capsazepine. Previous biological and pharmacological evidence suggested that vanilloid receptors were present in the brain. Our results demonstrate that the pharmacological properties of both the peripheral and central receptor sites display appropriate pharmacological similarity to represent the same receptor class. The modest differences in ligand affinities for the vanilloid receptor expressed in the brain nuclei and the dorsal root ganglion neurons may correspond to differences in sequence, modification or associated proteins.
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Affiliation(s)
- Tamas Szabo
- Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institute of Mental Health, Bldg. 37, Room 3A01, 37 Convent Drive, MSC 4255, Bethesda, MD 20892, USA
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Silva C, Avelino A, Souto-Moura C, Cruz F. A light- and electron-microscopic histopathological study of human bladder mucosa after intravesical resiniferatoxin application. BJU Int 2001; 88:355-60. [PMID: 11564021 DOI: 10.1046/j.1464-410x.2001.02339.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the morphology of bladder mucosa and the integrity of its mucin coat in patients with detrusor hyper-reflexia treated with intravesical resiniferatoxin. PATIENTS AND METHODS Seven patients with detrusor hyper-reflexia were treated intravesically with resiniferatoxin dissolved in 10% ethanol in saline (50 nmol/L solution in two and 100 nmol/L in five). Patients were clinically evaluated by a voiding chart and filling cystometry before and 3 months after each resiniferatoxin application. In addition, they underwent cystoscopy and bladder biopsies at 22-33 months after the first instillation and at 7-23 months after the last one. Tissue samples for light microscopy were fixed in 4% paraformaldehyde, embedded in paraffin and stained with haematoxylin-eosin or periodic acid-Schiff reagent (PAS). Those for electron microscopy were fixed in 5% glutaraldehyde and embedded in resin. RESULTS The resiniferatoxin instillation was not painful. Three months after treatment the mean voiding frequency decreased and five incontinent patients became continent. The maximum cystometric capacity increased in all patients; at cystoscopy the bladders appeared normal. On light microscopy the urothelium was of normal morphology and stained with PAS in the luminal cells and in the basement membrane. Mononuclear inflammatory cells were occasionally apparent in the lamina propria. On electron microscopy epithelial cells were visible in a thick basal lamina. Superficial cells had the usual irregular contour and contained numerous membrane-coated vesicles. In the lamina propria, unmyelinated axonal profiles with occasional varicosities could be identified. CONCLUSIONS Intravesical resiniferatoxin improved urinary frequency, incontinence and bladder capacity in patients with detrusor hyper-reflexia, causing no morphological change in the bladder mucosa. The PAS reactivity of the carbohydrate moieties present in the mucin coat and the basement membrane was unchanged by resiniferatoxin.
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Affiliation(s)
- C Silva
- Department of Urology, Hospital São João, Portugal
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Lee JC, Yang CC, Kromm BG, Berger RE. Neurophysiologic testing in chronic pelvic pain syndrome: a pilot study. Urology 2001; 58:246-50. [PMID: 11489711 DOI: 10.1016/s0090-4295(01)01143-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Studies of male chronic pelvic pain syndrome (CPPS) have generally centered on the pathologic features of the prostate rather than on the neurology of pain. Electrodiagnostic studies examine the integrity of somatosensory nerve pathways consisting of large, group A fibers. Heat sensation and visceral (autonomic) pain is mediated through small, unmyelinated C fibers, which can be tested cutaneously by thermal sensory analysis. We hypothesized that CPPS pain is mediated by these small C fibers. METHODS All subjects and controls had no history of neurologic disease and had normal neurologic examinations. Phase I: 14 patients with CPPS underwent electrodiagnostic testing using pudendal somatosensory evoked potentials and bulbocavernosus reflex latency measurements. Phase II: 31 patients with CPPS and 14 controls underwent thermal sensory analysis testing on the perineum and anterior thigh using noxious heat stimuli. Subjects used a computer-generated visual analog scale to dynamically report their discomfort. The peak and slope of the computer-generated visual analog scale were analyzed. RESULTS Phase I: two patients had delayed latency of the somatosensory evoked potentials, but additional evaluation with magnetic resonance imaging revealed no definable lesion. Phase II: with thermal sensory analysis, men with CPPS reported higher intensity pain at lower temperatures (P = 0.03). Men with CPPS also had higher peak computer-generated visual analog scale scores on perineal testing. No difference in thermal testing on the anterior thigh was found between the two groups. CONCLUSIONS Large, myelinated somatic fibers do not play a significant role in the pathophysiology of CPPS. Patients with CPPS have an altered sensation of perineal pain elicited by heat, which may represent a C-fiber-mediated effect.
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Affiliation(s)
- J C Lee
- Department of Urology, University of Washington, Seattle, Washington 98195-6510, USA
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Sterner O, Szallasi A. Novel natural vanilloid receptor agonists: new therapeutic targets for drug development. Trends Pharmacol Sci 1999; 20:459-65. [PMID: 10542446 DOI: 10.1016/s0165-6147(99)01393-0] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The discovery that compounds lacking a recognizable vanillyl-like motif might act as vanilloids has given new impetus to a search for novel vanilloid receptor agonists and antagonists in compound libraries. The availability of cell lines transfected with a cloned human vanilloid receptor will further expedite this search. In this article, the pharmacological properties of unsaturated dialdehydes and triprenyl phenols that represent two newly discovered chemical classes of vanilloids will be discussed. The existence of vanilloid receptors in several brain nuclei as well as in non-neuronal tissues predicts novel, innovative therapeutic indications for vanilloids. However, these findings also suggest that vanilloids might cause side-effects. An exploration of the uses of unsaturated dialdehydes in indigenous medicine might help identify new therapeutic targets for vanilloids and avoid unwanted actions.
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Affiliation(s)
- O Sterner
- Department of Organic Chemistry 2, University of Lund, S-221 00 Lund, Sweden.
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Sullivan J, Abrams P. The overactive bladder: neuropharmacological basis of clinical management. Curr Opin Obstet Gynecol 1999; 11:477-83. [PMID: 10526925 DOI: 10.1097/00001703-199910000-00011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The overactive bladder continues to pose a major challenge to clinicians treating lower urinary tract disorders, not least because our understanding of the pathogenesis of detrusor overactivity is still relatively limited. However, progress in understanding the basis of the overactive bladder is moving steadily forward, accompanied by a growing number of different forms of treatment. New pharmacological treatments and variations in the mode of delivery of older agents offer hope of efficacy with fewer side-effects. Neuromodulation is also offering a viable alternative to surgery in patients unresponsive to medical treatment.
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Affiliation(s)
- J Sullivan
- Bristol Urological Institute, Southmead Hospital, UK.
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Szabo T, Olah Z, Iadarola MJ, Blumberg PM. Epidural resiniferatoxin induced prolonged regional analgesia to pain. Brain Res 1999; 840:92-8. [PMID: 10517956 DOI: 10.1016/s0006-8993(99)01763-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Adequate treatment of cancer pain remains a significant clinical problem. To reduce side effects of treatment, intrathecal and epidural routes of administration have been used where appropriate to reduce the total dose of agent administered while achieving regional control. Resiniferatoxin (RTX), an ultrapotent capsaicin analog, gives long-term desensitization of nociception via C-fiber sensory neurons. We evaluate here the analgesic effect on rats of epidurally administered RTX, using latency of response to a thermal stimulus in unrestrained animals. Results were compared with those for systemically administered RTX. Vehicle or graded doses of RTX were injected subcutaneously (s.c.) or through an indwelling lumbar (L4) epidural catheter as a single dose. Both routes of application of RTX produced profound thermal analgesia, reaching a plateau within 4-6 h and showing no restoration of pain sensitivity over 7 days. Vehicle was without effect. For the epidural route, the effect was selective as expected for the targeted spinal cord region, whereas the subcutaneous administration of RTX had a generalized analgesic effect. At doses yielding a tripling of back paw withdrawal latency, epidural treatment was 25-fold more effective than the subcutaneous route of application. Consistent with the regional selectivity of the lumbar epidural route, the front paws showed no more effect than by systemic RTX treatment. Binding experiments with [3H]RTX provided further evidence of the segmental desensitization induced by epidural RTX. We conclude that epidural administration of RTX at the lumbar spinal level produces profound, long-lasting, segmental analgesia to C-fiber mediated pain in the rat.
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Affiliation(s)
- T Szabo
- Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institute of Health, Bldg 37, Rm 3A01 9000 Rockville Pike, Bethesda, MD 20892, USA
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