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Objective To compare and analyze the effectiveness of different pruritogens on the itch model in rats. Methods A total of 240 healthy male SD rats aged 3 to 4 months were selected and divided into 3 groups: histamine-dependent pruritogens group (histamine phosphate, compound 48/80), non-histamine-dependent pruritogens group (5-HT, chloroquine and endothelin-1) and normal saline control group. The neck and cheek were selected as the itching area to compare the itching effects of different doses (low, medium and high concentrations) of pruritogens within 30 min after intradermal injection. The difference in the frequency of hind limb scratching was recorded by using the hind limb magnetic ring combined with behavior recording box system. The changes of sensory nerve endings evoked potential in the skin and the mast cells in subcutaneous tissue were observed and analyzed by means of multi-channel physiological signal acquisition and processing system and toluidine blue staining. Results In the histamine-dependent pruritogens group, only compound 48/80 at medium and high concentrations induced the increment of times of neck and cheek scratching, which was significantly different from the control group (P < 0.05); increases in frequency and amplitude of sensory nerve endings evoked potential (P < 0.05); and elevated number of mast cells near the blood vessels in the subcutaneous tissue (P < 0.05). And, increased times of scratching in neck and cheek were observed in the phosphohistamine group after injection of the 3 concentrations (P < 0.05). High concentration enhanced the frequency of subcutaneous evoked potential and increased the number of mast cells between the control group and the histamine phosphate group (both P < 0.05). Conclusion The best itch effectiveness is induced by 5-HT in rats, even with low concentration. While, histamine-dependent pruritogens compound 48/80 and non-histamine-dependent pruritogens chloroquine and endothelin-1 are only effective at medium to high concentrations. Histamine fails to induce scratching behaviors, and is difficult to induce the model.

Aims: The search for plant-based treatments against atopic dermatitis (AD), a relapsing dermatological condition with high prevalence in tropical regions, has always been attracting special attention. Among many folk remedies for AD, Oroxylum indicum Linn (Bignoniaceae) is a commonly used medicinal plant whose effectiveness has not yet been scientifically reported. This study thus aimed to investigate the anti-AD activity of ethyl acetate extract from the bark of Oroxylum indicum. The plant, known as midnight horror or Indian trumpet flower plant distributed throughout different areas of Southeast Asia. Methodology: Five cream formulations containing Oroxylum indicum ethyl acetate bark extract in different concentrations (0%, 1.25%, 2.5%, 3.75%, and 5%) were topically applied onto the dorsal skin of 2,4-dinitrochlorobenzene-sensitized BALB/C mice once a day during 6 weeks. Phosphate-Buffered Saline (PBS) and Protopic (Tacrolimus 0.1%) were used as negative and positive control, respectively. All mice were subjected to the assessment of AD-like symptoms including the development of eczematous skin lesions, intensity of pruritus and histological alterations. Results: The plant extract at 5% was significantly effective in suppressing the dermatitis scores by 23.26% (n=6, p Conclusion: These results confirmed the inhibitory effect of Oroxylum indicumon the advance of AD at 5% when incorporated into a cream formulation and revealed the plant’s therapeutic potential in the approach to disease treatment. However, more studies on the immunosuppressive mechanism of the extract and the interplaying roles of main phytocomponents should ultimately support the utilization of this valuable medicinal plant.

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is associated with intestinal microflora. Since specific probiotics may have better efficacy for AD, we determined the efficacy of Pediococcus acidilactici SRCM102024 (PA) for treating AD in HaCaT cells and NC/Nga mice and explored the mechanism of action. AD-like pathology was induced in HaCaT cells and the dorsal skin of Nc/Nga mice by local exposure to 2,4-dinitrochlorobenzene (DNCB). In AD-lesion induced mice, PA in low-, medium- and high-dosages (5 × 10E6, 5 × 10E7 and 5 × 10E8 CFU/kg bw, respectively) and dexamethasone (3 mg/kg bw, positive-control) were orally administered for 5 weeks. The clinical AD severity, serum immunoglobulin E (IgE) and TNF-α, gene expressions of interleukin (IL)-4, IL-13, and TNF-α and gut microflora were measured. PA treatment (100–300 CFU/mL) dose-dependently increased cell survival in DNCB-induced HACAT cells. PA reduced the relative mRNA expression of PAR-2, TNF-α, IL-4 and IL-13 in the cells. In dorsal skin of Nc/Nga mice applied with DNCB, PA dose-dependently attenuated erythema, hemorrhage, edema, excoriation, dryness and scratching behavior and PA-H improved the clinical symptoms similar to the positive-control. PA-M and PA-H treatment significantly prevented the disturbance of the dorsal skin tissues and decreased the inflammatory cellular infiltrate of mast cells, compared to the control. PA dose-dependently reduced serum IgE and TNF-α concentrations and the mRNA expression of TNF-α, IL-4, and IL-13 in dorsal skin. In gut microflora, relative counts of Lactobacillales, Butyricicoccus and Ruminococcus were decreased in the AD-control compared to the positive-control and the PA-M and PA-H prevented their decrease. However, the positive-control increased serum AST and ALT activities, indicating liver damage as an adverse effect. In conclusion, oral treatment of PA (human equivalent 1 × 10E9-1 × 10E10) relieved the AD symptoms by dose-dependently preventing over-activation of the immune response. Oral PA intake may be a safe and effective alternative therapy for AD.

Objectives The objective of this study was to determine kitten preferences towards different scratchers and the effects of catnip and cat odor on kitten scratching behaviors. Methods Two-choice preference tests were conducted to compare scratchers and preferred scratchers with or without additives (ie, catnip, catnip oil, cat hair) in six studies. Kittens (n = 40, Results In study 1, the S-shaped cardboard was preferred over a hemp post with a toy on top, and no difference was observed in the other pairs of scratchers compared. In study 2, the S-shaped cardboard was preferred by kittens compared with a raised scratcher covered with window screen or with carpet, and no differences were observed between the latter two scratchers. In study 3, the scratcher covered with window screen set upright was preferred over the same scratcher laid horizontally on the floor. The S-shaped cardboard was preferred over the scratcher covered with bubble wrap. In study 4, kittens preferred the S-shaped cardboard over the scratchers covered with window screen or short-fiber carpet but not over the scratcher covered with long-fiber carpet. In study 5, the S-shaped cardboard was strongly preferred over the long cardboard and rectangular cardboard but not over the boat-shaped cardboard. In study 6, dried catnip plant, catnip oil spray or the hair from other cats did not alter the scratching behavior exhibited by the kittens vs the control S-shaped cardboard alone. Conclusions and relevance The S-shaped cardboard scratcher was a preferred scratcher for kittens. Catnip or odor of other cats did not alter this behavior in kittens. S-shaped cardboard may be a preferred scratching device for kittens.

SUMMARY Itch is a discrete and irritating sensation tightly coupled to a drive to scratch. Acute scratching developed evolutionarily as an adaptive defense against skin irritants, pathogens, or parasites. In contrast, the itch-scratch cycle in chronic itch is harmful, inducing escalating itch and skin damage. Clinically and preclinically, scratching incidence is currently evaluated as a unidimensional motor parameter and believed to reflect itch severity. We propose that scratching, when appreciated as a complex, multidimensional motor behavior, will yield greater insight into the nature of itch and the organization of neural circuits driving repetitive motor patterns. We outline the limitations of standard measurements of scratching in rodent models and present new approaches to observe and quantify itch-evoked scratching. We argue that accurate quantitative measurements of scratching are critical for dissecting the molecular, cellular, and circuit mechanisms underlying itch and for preclinical development of therapeutic interventions for acute and chronic itch disorders., In brief Scratching is a complex, multidimensional motor behavior reflective of itch sensation. Wimalasena et al. discuss methods to assess scratching behavior in humans and animal models. Using high-speed recording, they outline novel approaches for detailed observation and quantification of scratching behavior, going beyond incidence to identify new scratching-related parameters.

Objectives: This study was conducted to clarify the effects of agarwood on histamine release from mast cells in rats and on the scratching behaviors in mice. Methods: Histamine release from rat mast cells induced by compound 48/80 or concanavalin A (Con A) and compound 48/80-induced scratching behavior in mice were examined to investigate

Objectives: This study was conducted to clarify the effects of agarwood on histamine release from mast cells in rats and on the scratching behaviors in mice. Methods: Histamine release from rat mast cells induced by compound 48/80 or concanavalin A (Con A) and compound 48/80-induced scratching behavior in mice were examined to investigate the effects of agarwood. The hyaluronidase activity and the 3’,5’-cyclic adenosine monophosphate (cAMP) levels in mast cells were examined to investigate the mechanisms for the inhibition of histamine release. The correlation between the inhibitory effects of agarwood on histamine release and the content of its typical ingredients, a 2-(2-phenylethyl)chromone derivatives, was analyzed using thin-layer chromatography. Results: Agarwood showed an inhibitory effect on mast-cell histamine release induced by compound 48/80 or Con A without any effect on hyaluronidase activity; this effect involves an increase in the cAMP levels in mast cells. Oral administration of agarwood showed an inhibitory effect on compound 48/80-induced scratching behavior in mice. The inhibitory effects of agarwood on histamine release were quite different, depending on the area where the agarwood was produced, its quality, and its market price. No correlation was found between the inhibitory effects of agarwood on histamine release and the typical ingredients of agarwood, which are 2-(2-phenylethyl)chromone derivatives. Conclusion: These results show that agarwood inhibits histamine release from mast cells partially through an increase in the cAMP levels in cells. We suggest that some active ingredients of agarwood must be effective on oral intake and that agarwood can be used to treat patients with a number of conditions, including urticaria, atopic dermatitis, and bronchial asthma, in which an increase in histamine release occurs. Differences in the pharmacological effects of this crude drug among markets may provide important information for the quality control of this herbal medicine.

Perilla (Perilla frutescens L.) leaves have shown therapeutic efficacy in the treatment of inflammatory disorders, allergies, bronchial asthma, and systemic damage due to free radicals. In the present study we analyzed the active constituents in perilla leaves using high-performance liquid chromatography (HPLC) and isolated luteolin, a polyphenolic flavonoid. We investigated the anti-inflammatory and antipruritic properties of luteolin. Luteolin inhibited the secretion of inflammatory cytokines such as interleukin-1β (IL-1 β) and tumor necrosis factor-α (TNF-α) from human mast cells (HMC-1) stimulated with phorbol myristate acetate plus calcium ionophore A23187 in a dose-dependent manner. Luteolin also significantly reduced the histamine release from rat peritoneal mast cells stimulated by compound 48/80, a potent histamine liberator. Furthermore, the administration of luteolin markedly inhibited the scratching behavior and vascular permeability induced by pruritogens, such as compound 48/80 or serotonin, in ICR mice. These results suggested that luteolin has potential as a therapeutic agent against inflammation and itch-related skin diseases.

Summary Hemokinin-1 (HK-1) and endokinins are peptides predicted from a new mammalian tachykinin gene, TAC4. The amino acid sequences derived from rat/mouse HK-1 and human HK-1 are not identical; however, the effects induced by intracerebroventricular or intrathecal administration of HK-1 are attenuated by treatment with antagonists of neurokinin 1 (NK1) receptor, substance P (SP) receptor, indicating that HK-1 is an agonist of the NK1 receptor. On the other hand, a growing body of evidence indicates that pharmacological characteristics of HK-1 and SP are always not identical, suggesting that the HK-1-preferred receptor may be involved in the effects of HK-1. Endokinins are derived from human TAC4 and consist of four endokinins, endokinin A (EKA), endokinin B (EKB), endokinin C (EKC) and endokinin D (EKD). Effects induced by intrathecal administration of EKA/B (the common C-terminal decapeptide in EKA and EKB) and SP were very similar, while the effects of SP and EKA/B were inhibited by EKC/D (the common C-terminal duodecapeptide in EKC and EKD). This inhibitory effect of EKC/D was derived from leucine at the carboxyl-terminus. These findings suggest that HK-1 and EKA/B have an agonistic effect, while EKC/D has an antagonistic effect on the NK1 receptor in nociceptive processing.

Article commented: Kremer AE, Martens JJ, Kulik W, Rueff F, Kui-per EM, van Buuren HR, van Erpecum KJ, Kon-drackiene J, Prieto J, Rust C, Geenes VL, Williamson C, Moolenaar WH, Beuers U, Oude El-ferink RP. Lysophosphatidic acid is a potential mediator of cholestatic pruritus. Gastroenterology 2010; 139:1008-18. Original Abstract: Background & aims. Pruritus is a common and disabling symptom in cholestatic disorders. However, its causes remain unknown. We hypothesized that potential pruritogens accumulate in the circulation of cholestatic patients and activate sensory neurons. Methods. Cytosolic free calcium ([Ca(2+)] (i)) was measured in neuronal cell lines by ratiometric fluorometry upon exposure to serum samples from pruritic patients with intrahepatic cholestasis of pregnancy (ICP), primary biliary cirrhosis (PBC), other cholestatic disorders, and pregnant, healthy, and nonpruritic disease controls. Putative [Ca(2+)] (i)-inducing factors in pruritic serum were explored by analytical techniques, including quantification by high-performance liquid chromatography/mass spectroscopy. In mice, scratch activity after intradermal pruritogen injection was quantified using a magnetic device. Results. Transient increases in neuronal [Ca(2+)] (i) induced by pruritic PBC and ICP sera were higher than corresponding controls. Lysophosphatidic acid (LPA) could be identified as a major [Ca(2+)] (i) agonist in pruritic sera, and LPA concentrations were increased in cholestatic patients with pruritus. LPA injected intradermally into mice induced scratch responses. Autotaxin, the serum enzyme converting lysophosphatidylcholine into LPA, was markedly increased in patients with ICP vs. pregnant controls (P < 0.0001) and cholestatic patients with vs. without pruritus (P < 0.0001). Autotaxin activity correlated with intensity of pruritus (P < 0.0001), which was not the case for serum bile salts, histamine, tryptase, substance P, or mu-opioids. In patients with PBC who underwent temporary nasobiliary drainage, both itch intensity and autotaxin activity markedly decreased during drainage and returned to preexistent levels after drain removal. Conclusions. We suggest that LPA and autotaxin play a critical role in cholesta-tic pruritus and may serve as potential targets for future therapeutic interventions.

総説, アトピー性皮膚炎の経過には心理社会的要因が関与することが明らかとなり,2009 年版日本皮膚科学会による「アトピー性皮膚炎診療ガイドライン」にも基本的治療のひとつとして心身医学的側面からの治療が明記された.今回,39 歳,男性,通院は不定期で増悪により当科入院となったアトピー性皮膚炎患者につき検討した.本例は悪化時のみの受診,治療への意欲がない等から,アトピー性皮膚炎における心身症の分類では「治療・管理への不適応」に相当すると考える.客観評価では抑うつやストレスはなかったが,共感の過程で家族,仕事のストレスが判明し自身が掻破行動との関連を自覚するに至った.これら心身医学的側面からの評価・加療と,痒みに対する行動療法,生活や外用療法指導,疾患に関する知識の教育を行い,2 週間で軽快退院となった.アトピー性皮膚炎加療にあたり,時には精神科医のアドバイスを求めながら,心身医学的治療を行う必要性は高いと考えた.

Since anticonvulsants have been used for treating neuralgias, an interest has arisen to experimentally test vigabatrin for its gabaergic mechanism of action. For this, 41 Wistar rats were used, and in 25 of them a constrictive sciatic neuropathy was induced (Bennet & Xie model). For testing pain symptoms, spontaneous (scratching) and evoked behaviors to noxious (46o C) and non-noxious (40o C) thermal stimuli were quantified. Moreover, a comparative pharmacological study of vigabatrin with other analgesic anticonvulsant drugs was also performed. The results showed a possible dose-dependent analgesic effect of vigabatrin (gamma-vinyl-GABA) on experimental neuropathic pain, as shown by the significant (p

Since anticonvulsants have been used for treating neuralgias, an interest has arisen to experimentally test vigabatrin for its gabaergic mechanism of action. For this, 41 Wistar rats were used, and in 25 of them a constrictive sciatic neuropathy was induced (Bennet & Xie model). For testing pain symptoms, spontaneous (scratching) and evoked behaviors to noxious (46o C) and non-noxious (40o C) thermal stimuli were quantified. Moreover, a comparative pharmacological study of vigabatrin with other analgesic anticonvulsant drugs was also performed. The results showed a possible dose-dependent analgesic effect of vigabatrin (gamma-vinyl-GABA) on experimental neuropathic pain, as shown by the significant (pO uso de anticonvulsivantes no tratamento de neuralgias despertou um interesse em testar novas drogas anticonvulsivantes, e dentre essas a vigabatrina por possuir mecanismo de ação gabaérgico. Para isso, foram usados 41 ratos Wistar e em 25 deles induziu-se neuropatia ciática constritiva (modelo de Bennett & Xie). Para testar sintomas de dor, foram quantificados comportamentos espontâneos (coçar-se) e evocados, por meio de estímulos térmicos nocivos (46oC) e não-nocivos (40oC). Além disso, realizou-se estudo comparativo da vigabatrina com outros anticonvulsivantes analgésicos. Os resultados mostraram um possível efeito analgésico, dose-dependente, de vigabatrina (gama-vinil-GABA) em dor neuropática experimental. Isso foi evidenciado pela diminuição significativa (p

Since anticonvulsants have been used for treating neuralgias, an interest has arisen to experimentally test vigabatrin for its gabaergic mechanism of action. For this, 41 Wistar rats were used, and in 25 of them a constrictive sciatic neuropathy was induced (Bennet & Xie model). For testing pain symptoms, spontaneous (scratching) and evoked behaviors to noxious (46o C) and non-noxious (40o C) thermal stimuli were quantified. Moreover, a comparative pharmacological study of vigabatrin with other analgesic anticonvulsant drugs was also performed. The results showed a possible dose-dependent analgesic effect of vigabatrin (gamma-vinyl-GABA) on experimental neuropathic pain, as shown by the significant (p

While considerable effort has been made to investigate the neural mechanisms of pain, much less effort has been devoted to itch, at least until recently. However, itch is now gaining increasing recognition as a widespread and costly medical and socioeconomic issue. This is accompanied by increasing interest in the underlying neural mechanisms of itch, which has become a vibrant and rapidly-advancing field of research. The goal of the present forefront review is to describe the recent progress that has been made in our understanding of itch mechanisms.

Scratching behaviour in cats is described as a normal expression of the feline ethogram, having different possible purposes related to visual and chemical communication. During behavioural consultations owners often mention scratching as an additional problem. This preliminary study aimed to understand the characteristics of this complex behaviour by examining the variables displayed by a sample of the Italian feline population using multiple correspondence analysis. One hundred and twenty-eight cats were screened by means of a questionnaire to identify features of their scratching behaviour. Our data showed the importance of both the presence/absence of a scratching post in the cat’s living area and its relationship to marking. When a scratching post is present in a cat’s living area, the cat appears to use it. Some aspects related to sex, neutering, age and environmental characteristics may modify the expression of scratching as a marking behaviour. Research has led to increased knowledge of this behaviour and may help veterinarians in describing to owners why it is important for cats to express scratching behaviour in their environment. Such information could help veterinarians and owners to recognise normal and problematic scratching behaviours.

To clarify the mechanisms by which compound 48/80 (C48/80) induces scratching behavior, the involvement of dopamine D(1) receptors was investigated. The intracisternal (i.t.) administration of SCH23390 (1.0 μg), a selective dopamine D(1) receptor antagonist, significantly decreased C48/80-induced scratching behavior in mice. These results suggest that dopamine D(1) receptors contribute to scratching behavior or the itch sensation induced by subcutaneous injection of C48/80 in mice. Co-administration of SCH23390 and C48/80 enhanced c-fos immunoreactivities in the peduncular part of the lateral hypothalamus (PLH), whereas the immunoreactivities in the other groups were unchanged. The dopaminergic system may be playing an important role in the suppression of C48/80-induced scratching behavior by SCH23390.

Yokukansan (YKS) has been used in Japan as a remedy for neurosis, insomnia, and children with night crying. In a previous study, we reported that YKS controls scratching behavior and inhibits the development of atopic dermatitis (AD)-like lesions in NC/Nga mice. In this study, we investigated the effects of YKS on the development of AD-like lesions in socially isolated NC/Nga mice compared with the effects of fexofenadine and elucidated the mechanism of the ameliorating effect of YKS on the skin lesions. Ten-week-old male NC/Nga mice were divided into three groups (n = 5/group): the conventional control, the YKS-treated, and the fexofenadine-treated groups, and were kept isolated under conventional conditions for 6 weeks. Measurements were made of dermatitis scores and transepidermal water loss (TEWL), scratching and grooming behaviors. Immunohistochemistry and mRNA levels were also evaluated. We performed similar experiments under specific pathogen free (SPF) conditions that served as a SPF control. YKS and fexofenadine inhibited the aggravation of skin lesions and decreased TEWL, but only YKS decreased the numbers of scratching and pathologic grooming behaviors. Immunohistochemistry and RT-PCR revealed that N-methyl-D: -aspartate (NMDA) receptor expression was increased in the skin of conventional control mice and was decreased in YKS-treated mice. Glutamate transporter-1 (GLT-1) mRNA levels were decreased in the skin of conventional control mice and were increased in YKS-treated mice. The results indicate that YKS ameliorates AD-like skin lesions in NC/Nga mice through a mechanism distinct from that of fexofenadine. Furthermore, the effects of YKS are suggested to be mediated via glutamate signaling in the skin lesions.

We report a case of 7-year-old monozygotic twin patients with atopic dermatitis. The HLA haplotypes were HLA A2, A11, B27, B61, DR1, and DR4. Both serum IgE levels and cedar pollen radioallergosorbent test (RAST) scores were high in the twins (elder/younger sister: IgE: 5170/3980 IU/ml and Japansese cedar pollen: >100/64.0) in contrast to low mite and food RAST scores (Dermatophagoides Pterygonium; 0.59/0.4 and egg white 9.24/4.6). The patients showed positive immediate (20 min in both sisters) and delayed (24 hours in elder sister, 24, 48, 72 hours in younger sister) reactions to a scratch test with Japanese cedar pollen. Skin lesions on the face were aggravated and extended to the trunk and extremities during the Japanese cedar pollen season and gradually subsided in summer. Oral provocation with egg white or cow milk showed no exacerbations, and topical corticosteroid did not improve the eczema. In contrast, successful protection from severe scratching behaviors was achieved by use of topical anti-allergic eye drops and wearing nightgowns made by the mother.

Scratching behavior observed after epicutaneous challenge with the antigen 2,4-dinitrofluorobenzene (DNFB) in the ear of BALB/c mice passively sensitized with anti-dinitrophenol (DNP). Immunoglobulin (Ig) E was characterized pharmacologically and compared with that caused by compound 48/80. Although DNFB application itself caused scratching behavior in non-sensitized mice, the number of scratchings apparently increased in sensitized mice from 60 min after antigen application in comparison with non-sensitized control mice. Prednisolone, cyproheptadine, dibucaine and naloxone significantly inhibited the DNFB-induced scratching behavior, whereas the histamine H 1 -receptor antagonists HSR-609, cetirizine and terfenadine only showed a tendency to inhibit scratching. Injection of 48/80 into the rostral part of the back also caused scratching. The first scratching was observed within 10 min after injection and lasted intermittently for 30 min. The 48/80-induced scratching was markedly inhibited by cyproheptadine, dibucaine and naloxone, but not by prednisolone and the histamine H 1 -receptor antagonists. Ear edema caused by DNFB application in sensitized mice was markedly inhibited by prednisolone, HSR-609, cetirizine, terfenadine and cyproheptadine, whereas dibucaine and naloxone failed to affect ear edema. These results indicate that scratching behavior could be induced in mice in association with an IgE-mediated allergic cutaneous reaction and that the reaction is pharmacologically similar, but not identical, to that caused by 48/80. Although histamine is considered to participate in the formation of ear edema, it may not play an important role in the generation of scratching.

研究科: 千葉大学大学院薬学研究院, 修了年:2007, 学位:千大院医薬博乙第医薬9号

Title Olopatadine hydrochloride inhibits scratching behavior induced by a proteinase-activated receptor 2 agonist in mice. Author(s) Yoshizaki, Ayumi; Sato, Shinichi Citation Journal of dermatological science, 56(2), pp.136-139; 2009 Issue Date 2009-11 URL http://hdl.handle.net/10069/22311 Right Copyright © 2009 Japanese Society for Investigative Dermatology Published by Elsevier Ireland Ltd. NAOSITE: Nagasaki University's Academic Output SITE

研究科: 千葉大学大学院薬学研究院, 修了年:2007, 学位:千大院医薬博乙第医薬9号