Cisplatin is a widely used chemotherapeutic drug for the treatment of solid tumors. However, the drug accumulates in the cochlea, and damages inner ear structures, resulting in bilateral andpermanent hearing loss. Previous data from our laboratory indicate that activation of the transient receptor potential vanilloid 1 (TRPV1) receptor (by capsaicin) increases the NOX3 isoform of NADPH oxidase, leading to the generation of reactive oxygen species (ROS) in the cochlea, transient cochlear inflammation and transient hearing loss. We also demonstrated that the transient inflammation was produced by ROS-mediated activation of signal transducer and activator of transcription 1 (STAT1). Surprisingly, over time, this response desensitizes and capsaicin was subsequently able to protect against cisplatin ototoxicity. The goal of this study was to determine the mechanism of otoprotection against cisplatin ototoxicity following the administration of capsaicin. For this study we utilize both an immortalized organ of Corti outer hair cells and rat cochlea. Capsaicin (2.5 µM) increased both Ser727 p-STAT1 and Tyr705 p-STAT3 implicating its role in inflammation. Expression of cannabinoid receptors were observed in UB/OC-1 cells as well as rat outer hair cells (OHCs). However, inhibition of CB2 receptors (by AM630) reduced capsaicin-mediated Tyr705 p-STAT3, but had little effect on Ser727 STAT1. Capsaicin protected UB/OC-1 cells against cisplatin-induced apoptosis. This protection was reversed by CB2 antagonist but potentiated by TRPV1 inhibition. Significant cell death was observed following treatment of UB/OC-1 cells with AM630 alone, underscoring the importance of CB2 receptors in survival of these cells. CB2 agonist, JWH, significantly increased the protective signal, STAT3. Furthermore, capsaicin-mediated protection was reversed by the inhibition of STAT3, implicating STAT3 in otoprotection. In animal studies, oral administration of capsaicin (0.5% solution) induced transient inflammation but led to a long term recovery. Animals pre-treated with oral capsaicin were protected against cisplatin-induced hearing loss as compared to vehicle-treated animals, suggesting protection against hearing loss. Capsaicin increased the expression of both CB1 and CB2 receptors in the organ of Corti, which might confer the long term protective actions of this agent against hearing loss. In rats pretreated with AM630, the protective action of capsaicin was abolished. We conclude that otoprotection mediated by capsaicin is produced by activation of CB receptors in the cochlea which are coupled to both STAT1 and STAT3 activation. However, our data support the conclusion that activation of STAT3 confers the otoprotective action of capsaicin. In contrast, activation of STAT1 by capsaicin could contribute to the transient inflammatory response previously observed in vivo. The net protective action of capsaicin could result from an increase in the STAT3/STAT1 ratio of cells in the cochlea, which antagonizes the ability of cisplatin lower this ratio and promote cell death.

No description available.

Release of substance P-like immunoreactivity (SP-LI) was measured from isolated perfused guinea-pig hearts. Capsaicin (1 μM) caused a substantial increase in the amount of SP-LI detected in perfusate compared to values during exposure to vehicle or drug-free buffer. Tachyphylaxis developed to the effect of capsaicin on release of SP-LI and to its effect on physiological parameters. These data show SP-LI can be released from cardiac sensory nerves and suggest SP could mediate a portion of the response of the isolated heart to capsaicin.

Die Osteoarthrose (OA) des Ellbogengelenks ist eine der wichtigsten Gelenkerkrankungen des Hundes, die sich aufgrund erblich bedingter Fehlstellung der Gelenke sekundär häufig schon bei sehr jungen Hunden entwickelt und zu einer verminderten Lebensqualität der Tiere führt. Im Laufe der Erkrankung kommt es zu einer Schädigung des Gelenkknorpels, der an Elastizität und Spannkraft verliert und seine Funktion, nicht mehr ausüben kann. Eine Ablösung von Knorpelfragmenten und Entzündungen im Gelenk können die Zerstörung des Gelenkknorpels beschleunigen. Die OA ist nicht heilbar. Das Therapieziel ist eine möglichst vollständige Schmerzreduktion und die Verbesserung der Lebensqualität. Eine chirurgische Denervation ist im Ellbogengelenk des Hundes ohne Traumatisierung anatomischer Strukturen nicht möglich. Ziel der vorliegenden Arbeit war es, erstmalig einen experimentellen Ansatz zur chemischen Denervation sensibler Gelenkafferenzen im Ellbogengelenk beim Beagle mit dem Neurotoxin OX7-Saporin durchzuführen. Zusätzlich wurden Substanzen aus der Humanmedizin zur Schmerzreduktion und symptomatischen Therapie der OA am Hund erprobt und der Therapieerfolg evaluiert. Im Rahmen eines Therapieversuches in der Klinik für Kleintiere der Universität Leipzig wurde bei zwei, an OA erkrankten Hunden Capsaicin einmalig intraartikulär injiziert. Der erste Hund erhielt intraartikulär 250 mg Capsaicin. Dieser Patient zeigte Nebenwirkungen in Form einer Herz- und Atemfrequenzerhöhung, starker Schmerzhaftigkeit und neurologischen Symptomen. Der zweite Hund wurde mit 83 mg Capsaicin behandelt und zeigte keine Nebenwirkungen. Sowohl die Bewertung der Besitzer als auch die orthopädische Untersuchung ergaben keine Verbesserung der Lahmheit. Vier kranken Hunden wurde ebenfalls im Rahmen eines Therapieversuches Botox (Botulinumtoxin A) intraartikulär einmalig injiziert. Drei Hunde wurden mit 50 Einheiten, ein Hund mit 100 Einheiten Botox behandelt. Die Applikation von Capsaicin und Botox führten zu keiner Verbesserung der Symptomatik. In der Humanmedizin ist die Schmerzbehandlung mit Capsaicin und Botox erfolgreich. Deshalb sollten diese Therapieansätze auch für die Anwendung beim Hund weiter optimiert werden. Das Neurotoxin OX7-Saporin wurde in einer Dosierung von 100 µg erstmalig in das Ellbogengelenk von drei Beagle-Hündinnen appliziert, um eine sensible Denervation des Gelenkes zu erreichen. Der retrograde Transport des Ribosomen-inaktivierenden Proteins in die Perikarya der Spinalganglienzellen, die das Ellbogengelenk sensibel innervieren, sollte eine selektive Zerstörung der Neurone durch das Neurotoxin bewirken. Der retrograde Tracer Fluoro-Gold wurde, zur Kontrolle der Wirkung des Neurotoxins, nach einer Wartezeit von 15 Tagen intraartikulär in das linke und das rechte Ellbogengelenk appliziert. Fluoro-Gold kann ausschließlich von intakten Nervenfasern transportiert werden. Die Ganglien C4 - Th3 wurden bilateral zur histologischen Auswertung entnommen und in Paraffin eingebettet. Zur Bestimmung der Gesamtneuronenanzahl wurden alle Neurone in jedem dritten Schnitt eines Ganglions gezählt. Die Summe dieser Nervenzellen ergab die Gesamtneuronenanzahl eines Ganglions. Die Einlagerung von Lipofuszin führte zu einer starken Autofluoreszenz im Zytoplasma der Neuronen. Alle Schnitte wurden mit Sudan-Schwarz gefärbt, um die Autofluoreszenz von der retrograden FG-Markierung zu unterscheiden. Die FG-Markierung konnte nur in den Ganglien C6 und Th1 im Zytoplasma sehr weniger Neuronen dokumentiert werden. Der histologische Nachweis einer Neurodegeneration nach Applikation des Neurotoxins OX7-Saporin in das linke Ellbogengelenk war negativ. In den untersuchten Spinalganglien wurden intakte Nervenzellen nachgewiesen. Auch die bilaterale intraartikuläre Injektion des retrograden Tracers FG war nicht erfolgreich. Aus den Ergebnissen dieser experimentellen Ansätze wird zusammenfassend geschlussfolgert: Ø Vor der Durchführung zukünftiger experimenteller Untersuchungen beim Hund muss die optimale Konzentration und die Wartezeit für das Neurotoxins OX7-Saporin ermittelt werden. Ø Die Rezeptoren für OX7-Saporin müssen an den Nervenzellen des Hundes zweifelsfrei nachgewiesen werden, bevor das Neurotoxin im caninen Tiermodell eingesetzt werden kann. Ø Die optimale Konzentration des Fluoreszenzfarbstoffes FG für intraartikuläre Injektionen und dessen retrograde Transportgeschwindigkeit beim Hund müssen ermittelt werden, bevor dieser Tracer wieder im Tierexperiment eingesetzt werden kann. Ø FG wurde als 1,8%ige Lösung in das Ellbogengelenk beim Beagle appliziert. Diese Konzentration war wahrscheinlich zu gering, um eine retrograde Markierung der sensiblen Neurone in den entsprechenden Spinalganglienzellen nachzuweisen. Ø Die intraartikuläre Applikation des Neurotoxins OX7-Saporin führte nicht zur selektiven Neurodegeneration. Eine Aussage zur Schmerzausschaltung und symptomatischen Therapie der OA des Hundes mit OX7-Saporin ist deshalb nicht möglich.

The present study investigated pharmacological properties of Capsicum frutescens-derived capsaicin, including its analgesic, anti-inflammatory and coagulatory properties. The effects of capsaicin on gastrointestinal and myocardial muscles, as well as on myocardial ischaemic-reperfusion, were also investigated. Capsaicin pre-treatment in neonatal rats has been found to abolish the development of thermal hyperalgesia produced in a model of neuropathic pain in rats (Toth-Kasa et al., 1986). In addition, capsaicin sensitivity has been found to be dependent on continued presence of nerve growth factor (NGF), whose concentration increases in inflamed tissues (Bevan and Winter, 1995). By stimulating the release of excitatory amino acids (EAA); such as glutamate and neuropeptides [(CGRP, neurokinin A (NKA) and Substance P (SP)] from both the peripheral and central terminals of sensory neurones by two mechanisms (Kroll et al., 1990; Del Bianco et al., 1991; Lou et al., 1992; 1994; Woolf et al., 1994); capsaicin has been shown to produce a longer-term inhibitory effect. This is one likely mechanism for capsaicin analgesic and anti-inflammatory actions (Bleakman et al., 1990). Within the gastro-intestinal tract, SP and NKA are involved in the physiological control of several digestive functions, such as motility, fluid and electrolyte secretion, blood flow, and tissue homeostasis (Otsuka, 1993; Holzer et al., 1997). Consistent with this finding, upsurge of SP in irritable bowel syndrome (IBD) was confirmed by Mantyh et al, (1988). Pre-treatment of rats with either capsaicin or NK-1R antagonists dramatically reduced fluid secretion, mucosal permeability, and intestinal inflammation in animal models of acute and chronic inflammation (McCafferty et al, 1994; Pothoulakis et al., 1994). Capsaicin can modulate endocrine and paracrine activities, immune responses, as well as gastro-intestinal and cardiovascular functions. Moreover, up-regulation of Substance P receptors was found to be associated with chronic inflammatory conditions (De et al., 1990). Stimulation of transient receptor potential vanilloid 1 also results in the activation of nociceptive and neurogenic inflammatory responses (Rigoni et al., 2003). vi The pharmacodynamic effects of capsaicin on the cardiovascular system remain elusive. Some actions of capsaicin on the heart were attributed to an interaction at K+ channels (Castle, 1992), or liberation of neuropeptides, most notably calcitonin-gene-related-peptide (CGRP) from the vanilloid-sensitive innervation of the heart (Franco-Cereceda et al., 1988; 1991). The possibility of a direct effect of capsaicin on the heart via a cardiac vanilloid receptor (VR), or through interaction of vanilloid receptors with purinergic receptors, and subsequent release of nitric oxide (NO), leading to vasodilatation were considered. Evidence abound in the literature that Ca2+ ions are released through 1, 4, 5 inositol phosphatase by the release of phospholipase C, or through interaction of the vanilloid receptors with cannabinoids. In an earlier study, Jaiarj et al. (1998) found that capsaicin acting on the heat-sensitive vanilloid receptors, had thrombolytic effects. Though weak evidence, Jaiarj et al. (1998) observed that individuals who consume large amounts of Capsicum have lower incidence of thromboembolism. Following ethical approval, the study reported in this thesis was conducted in phases. Identification of Capsicum frutescens (facilitated by a botanist in the Department of Botany, Westville campus of the University of KwaZulu Natal). Chromatographic extraction of capsaicin from Capsicum frutescens was followed by Nuclear Magnetic Resonance (NMR) analysis of the extract. Animal studies were conducted using capsaicin extract (CFE) and/or a reference capsaicin (CPF), using „hot plate. and „acetic acid. test methods to investigate the role of capsaicin on analgesia. Fresh egg albumin-induced inflammation was used to investigate the role of capsaicin in inflammation, following pre-treatment with CFE and CPF. Concentraton-response curves of increasing concentrations of capsaicin, acetylcholine and other agonist drugs with specific antagonists on strips of chick oesophagus, guinea-pig ileum, and rabbit duodenum were constructed following investigations on gastrointestinal (GIT) smooth muscles. The effect of capsaicin on coagulation was assessed by measuring international normalized ratio (INR) of animals that were exposed to different concentrations of capsaicin (CFE and CPF). Furthermore, parallel control studies were conducted in each of these investigations using distilled water or saline as placebo-control or specific-prototype agonists. negative-control. Cardiovascular investigations included studies on the effects of capsaicin on the heart rate, inotropy, vii coronary perfusion pressure, and ischaemic-reperfusion injury, using Langendorf.s rat heart models. Collated data were triangulated by manual hand-written and PowerLab data acquisition, or computerised capture. Statistical analysis were performed by either one or two of the following: Student.s t-test, ANOVA (repeated or single–use modes), facilitated and confirmed by Graph Pad Prism, Microsoft Excel or CPSS software(s). Reproducibility and relevance to the stated objectives of the various studies were confirmed by assessing which of the Null or Alternative hypothesis is validated by the results from the test. Treatment with CFE or CPF at all doses significantly (p<0.01) increased MRT. By comparison with control, writhing responses to acetic acid were significantly reduced following pre-treatment with various doses of CFE or CPF. The results in both parallel groups of CFE and CPF in the hot plate and acetic acid tests had Pearson correlation of one (1). Compared to the diclofenac (DIC) group, the degree of inhibition of paw oedema by CFE and CPF was statistically significant (P<0.05-0.001), best in the first 4 hours of treatment. The results of the in vitro laboratory animal study indicate that relatively low concentration of CPF (20 or 40 .g) produced significant (p.0.05), concentration-related inhibitions of acetylcholine (0.1-5 .g)-induced contractions of the chick isolated oesophagus, guinea-pig isolated ileum and rabbit isolated duodenum. Biphasic effects, which were noticed at low concentrations, consisted of initial brief contractions, followed by longer-lasting relaxations and reductions of the contractile amplitudes of the muscle preparations. Percentage inhibitions of the smooth muscle contractions by CFE or CPF were concentration-dependent, ranging from 20-70% (p<0.02). / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

Neste trabalho, avaliou-se a eficácia do uso da oleoresina de capsaicina, extraído das pimentas Malagueta, Red Savina e Bhut Jolokia, no tratamento da superfície de madeiras do gênero Pinus sp. com teores de umidade de equilíbrio de 12% e 0%. Os corpos de prova foram submetidos ao ataque de fungos Paecilomyces variotti e Pycnoporus sanguineus. Foi utilizado um preservante sintético conhecido comercialmente como stain para se comparar com a eficiência de preservantes naturais à base de oleoresina de capsaicina. A partir de medidas de ângulo de contato das superfícies das madeiras tratadas com o óleo de capsaicina, observou-se que a pimenta Bhut Jolokia e o preservante stain proporcionavam menor molhabilidade para a espécie de madeira estudada em ambos teores de umidade. O tratamento preservante fez com que a energia de superfície diminuísse se comparada aos valores de amostras de madeiras sem o tratamento preservante devido às contribuições polares e dispersivas. A análise estatística dos resultados, pelo método de Tukey, mostrou que não existe um grupo de resultados estatisticamente equivalente aos obtidos com a amostra testemunha (sem tratamento). As amostras de Pinus sp. a um teor de umidade 0% mostrou-se mais protegida superficialmente quando modificada com a oleoresina extraída da pimenta Bhut Jolokia e o mesmo efeito foi observado estatisticamente para o preservante stain. A técnica de Langmuir foi utilizada para melhor compreender as interações capsaicina/ergosterol, capsaicina/DPPG (dipalmitoil fosfatidil glicerol) e capsaicina/DPPG/ergosterol. A isotermas de pressão de superfície vs área por molécula se mostraram mais expandidas quando a subfase continha oleoresina de capsacina e quando comparada com as de lipídio puro (DPPG), indicando assim, a inserção da capsaicina na monocamada. Em linhas gerais, oleoresina de capsaicina extraída da pimenta Bhut Jolokia mostrou-se mais eficiente em todos os aspectos se comparada com as pimentas Red Savina e Malagueta, marcando, assim, uma potencialidade para uso como preservante natural de madeiras. / The present study evaluated the effectiveness of capsaicin oleoresin extracted from Malagueta, Red Savina and Bhut Jolokia peppers in the surface treatment of Pinus sp. with moisture contents of 12% and 0%. The samples were submitted to the attack of Paecilomyces variotti and Pycnoporus sanguineus fungus. A synthetic wood preservative, that is commercially known as stain, was used to compare the effectiveness of natural preservatives based on capsaicin oleoresin. From contact angle measurements for wood surfaces treated with capsaicin oleoresin, it was obtained that Bhut Jolokia pepper and stain preservatives have provided worse wettability for wood samples at both moisture contents. The preservative treatment caused a decrease in the surface energy when compared to the samples without preservative treatment due to polar and dispersive contributions. Statistical analysis for the results by using the Tukey method showed that there is not a group of results that are statistically equivalent to those obtained for the control samples (without treatment). Pinus sp. samples at a moisture content of 0% showed to be more surface protected after being modified with the oleoresin extracted from Bhut Jolokia; the same effect was observed statistically for stain. The Langmuir technique was used to better understand interactions among capsaicin/ergosterol, capsaicin/DPPG (dipalmitoyl phosphatidyl glycerol) and capsaicin/DPPG/ergosterol. Surface pressure vs. area per molecule isotherms appeared to be even more extended when the subphase contained capsaicin oleoresin instead of pure lipid (DPPG), thus indicating the inclusion of capsaicin into the monolayer. In general, the capsaicin oleoresin extracted from Bhut Jolokia proved to be more efficient in all the aspects of characterization when compared to Red Savina and Malagueta highlighting its potential for use as a natural wood preservative.

Nesse estudo, utilizamos a oleoresina de capsaicina, extraído da pimenta Malagueta (Capsicum frutensens) e da pimenta Dedo-de-moça (Capsicum baccatum), para a preservação de amostras de madeira contra o ataque do fungo Paecilomyces variotti. Os preservantes naturais foram aplicados em corpos de prova de madeiras do gênero Pinus sp. e Hymenae sp. (Jatobá) com as dimensões 5,0 x 3,0 x 1,0 (cm). A seguir, esses corpos de prova foram expostos ao fungo para o acompanhamento do seu desenvolvimento. As análises mostraram que o preservante natural retardou o crescimento do fungo, sendo a oleoresina de capsaicina extraído da pimenta Malagueta a mais eficiente se comparada à oleoresina extraída da pimenta Dedo-de-moça e ao óleo de linhaça. A partir da medida de ângulo de contato observou-se que o preservante de oleoresina da pimenta Malagueta proporcionava uma maior molhabilidade para as duas espécies de madeiras. A técnica de FTIR-ATR indicou que os preservantes não modificaram a estrutura das madeiras e a análise de raios X revelou que o desenvolvimento do fungo provocou uma perda de estabilidade e periodicidade nas estruturas das madeiras. Através do teste de proporção utilizado para a análise do desenvolvimento do fungo, comprovou-se estatisticamente que o seu crescimento foi menor para as amostras com os preservantes das pimentas. Pelo MEV foi possível visualizar as estrutura de hifas do fungo sobre a madeira. E a perda de massa para ambas as espécies de madeiras foram menores quando foram utilizados os preservantes, sendo o Pinus a espécie que sofreu maior degradação. / In this study, were used the oleoresin capsaicin, extracted from Capsicum frutensens and Capsicum baccatum, for the preservation of wood samples against the attack of the Paecilomyces variotti fungus. The natural preservatives were applied to Pinus sp. and Hymenaea sp. (Jatobá) specimens with the dimensions 5.0 x 3.0 x 1.0 (cm). Subsequently, these specimens were exposed to fungus and their development was monitored. . Analyses showed that the natural preservative slowed the growth of the fungus. Action of the oleoresin capsaicin extracted from Chilli pepper is the most efficient when compared to pepper oleoresin extracted from Capsicum frutensens and Capsicum baccatum and also with the linseed oil. The contact angle measured showed that the preservative of Oleoresin Chilli Pepper offered a higher wettability for both wood species. FTIR-ATR technique indicated that the preservatives did not change wood structure and X-ray analysis revealed that the development of the fungus caused a loss of stability and periodicity in the wood structures. At proportion test to analyze the development of the fungus, it was shown statistically that their growth was lower for the samples with preservatives peppers. It was possible to visualize the hyphae structure by scanning electronic microscopy technique. Mass loss of both wood specie was lower when preservative was used, and Pine species was more degraded.

Bibliography: leaves 152-170.

In searching for new human pain models that more closely resemble clinical pain states, the capsaicin pain model has emerged as a viable model for both inflammatory and neuropathic pain states. A principal benefit of the capsaicin model is that it allows study of two different pain processes, primary and secondary hyperalgesia. Primary hyperalgesia is characterized by spontaneous pain and both heat and mechanical hyperalgesia. In addition, it is likely the result of activation and sensitization of both peripheral and central nociceptors. In contrast, secondary hyperalgesia is characterized by only mechanical hyperalgesia and is caused by the sensitization of central nociceptive neurons. Previous research utilizing the capsaicin pain model has primarily focused on the neural properties with little focus on the impact of affective states on capsaicin-related pain processes. The present study examined the impact of a noise stressor on both primary and secondary hyperalgesia. Results indicated that the effects of the noise stressor impacted secondary hyperalgesia, but not primary hyperalgesia.

Stimulation of C-fiber sensory neurons innervating the respiratory tract with electricity or capsaicin leads to the liberation of substance P, CGRP and other neuropeptides from the nerve terminals. Substance P (SP) binds to the NK-receptors on the membrane of vascular endothelial cells and elicits neurogenic inflammatory responses. These inflammatory responses include plasma leakage and the subsequent edema formation (Lundberg and Saria, 1983¡FMcDonald et al., 1988). Evans blue is a hydrophilic dye and is often used as a tracer of plasma leakage due to its¡¦ high affinity to the plasma proteins. Plasma leakage causes Evans blue extravasates from the blood vessels and remains in the tissues. The more plasma leaks from the blood vessels, the more Evans blue will extravasate into the tissues. Measuring extravasated Evans blue dye that is extracted from tissues, is useful for evaluation of the amount of plasma leakage. Potassium channel openers can inhibit neurogenic plasma leakage in the airways and urinary bladder (Hollywood et al., 1998). Evans blue directly stimulates large-conductance Ca2+-activated K+ channels in cultured endothelial cells of human umbilical vein (Wu et al., 1999). This suggests that it may influence the permeability of the microvessels in vivo. A previous study shows that Evans blue dye blocks capsaicin-induced cough and bronchospasm in the guinea pig (Bolaer et al., 1995). We postulated that pretreatment with Evans blue may influence the extent of neurogenic inflammation in the rat airways induced by the application of either SP or capsaicin. India ink was used as a colloidal tracer dye to label the leaky vessels. The present study investigated whether different concentration of Evans blue (0, 3, 15 and 30 mg/ml/kg) pretreatment could affect the plasma leakage and edema formation in rat lower airways in response to intravenous injection of either SP or capsaicin. The amount of plasma leakage was expressed by the area density of India ink-labeled leaky blood vessels. We also investigated whether Evans blue influenced the ultra-structural change in tracheal serous cells induced by intravenous injection of SP. Our results showed that pretreatment with high concentration of Evans blue reduced more than seven tenths of the area density of plasma leakage in the trachea caused by SP application (P<0.01); reduced more than seven tenths in the left main bronchus (P<0.01) and reduced about seven tenths in the right main bronchus (P<0.01), compared to the control group that received saline prior to SP. However, no statistical significance was observed in edema ratio between any two groups (P>0.05). In the neurogenic inflammation of the airways caused by injection of capsaicin, pretreatment with high concentration of Evans blue reduced more than seven tenths of the area density of plasma leakage in the trachea (P<0.01); reduced more than seven tenths in the left main bronchus (P<0.01) and reduced about seven tenths in the right main bronchus (P<0.01), respectively, compared to the control group that received saline prior to capsaicin. Pretreatment with high concentration of Evans blue prior to capsaicin also reduced more than eight-tenth in edema ratio (P<0.01). In the ultra-structure change of serous cells and the stastical analysis of the number of active serous per 1000£gm2 of tracheal epithelium, Evans blue pretreatment prior to SP significantly reduced the number of active serous cells by seven tenths (P<0.01) as compared to control group that received saline prior to SP. Therefore, we concluded that pretreatment with high concentration of Evans blue exerted its¡¦ effect by opening large-conductance Ca2+-activated K+ channels and inhibited the plasma leakage induced by SP or capsaicin. But no significant inhibition was observed in edema formation induced by SP application. Low concentration of Evans blue might enhance the neurogenic inflammation of the airway. Under the observation with SEM, we found that SP activated serous cells in airway epithelium, and high concentration of Evans blue pretreatment lowered the secretory activity of serous cells. Therefore Evans blue might inhibit the activation of serous cells.