Effect of Brazilian propolis on scratching behavior induced by compound 48/80 and histamine in mice

We studied the effect of Brazilian propolis on scratching behavior induced by compound 48/80 and histamine in ICR mice. Propolis granular A.P.C dose-related inhibited scratching behavior induced by compound 48/80 and significant inhibition were observed at 1000 mg/kg. However, histamine-induced scratching behavior was not inhibited by propolis granular A.P.C even at 1000 mg/kg. Propolis ethanol extract at 10 microg/ml or more inhibited histamine release from rat mast cells induced by compound 48/80. In addition, it blocked increased vascular permeability induced by compound 48/80. The inhibitory effect of propolis on scratching behavior induced by compound 48/80 was gradually enhanced by repeated administration, and 500 mg/kg propolis granular A.P.C, which caused no effect through single administration, significantly inhibited scratching behavior after repeated administration for 4 weeks. From these findings, it is assumed that the inhibition of scratching behavior induced by propolis occurs through a mast cell-dependent mechanism.     

Caffeic acid inhibits compound 48/80-induced allergic symptoms in mice

The effect of caffeic acid on scratching behavior and vascular permeability changes induced by compound 48/80 in ICR mice were investigated. An oral dose of 500 mg/kg of caffeic acid significantly inhibited scratching behavior and vascular permeability induced by compound 48/80. The inhibitory effects of daily administration of lower doses of caffeic acid, 100 and 200 mg/kg, were also investigated; and it was found that 200 mg/kg significantly inhibited compound 48/80-induced scratching behavior after the second week of consecutive administration. The effect of 200 mg/kg of caffeic acid on scratching behavior was observed up to the third week of the treatment. The decrease in histamine content induced by compound 48/80 was significantly antagonized by 200 mg/kg. The findings suggest that caffeic acid may be effective for treating itch and edema in allergic dermatitis.     

Participation of histamine H1 and H2 receptors in passive cutaneous anaphylaxis-induced scratching behavior in ICR mice

Scratching behavior associated with passive cutaneous anaphylaxis was examined and compared to that induced by compound 48/80 or histamine in ICR mice. Elicitation of passive cutaneous anaphylaxis, and intradermal injections of compound 48/80, histamine or serotonin induced both scratching behavior and vascular permeability increase in ICR mice. In mast cell-deficient WBB6F1-W/Wv mice, although histamine induced scratching behavior and vascular permeability increase, passive cutaneous anaphylaxis was not observed. Cetirizine and terfenadine significantly inhibited the scratching behavior and vascular permeability increase caused by passive cutaneous anaphylaxis, compound 48/80 and histamine. The histamine H1 receptor antagonists inhibited the vascular permeability increase almost completely, whereas they failed to abolish the scratching behavior. Famotidine and ranitidine significantly inhibited the scratching behavior caused by histamine. The histamine H2 receptor antagonists did not affect the vascular permeability increase caused by histamine. The combination of cetirizine and ranitidine abolished the histamine-induced scratching behavior. The combination, however, failed to potentiate the inhibition of passive cutaneous anaphylaxis-induced scratching behavior significantly. The results indicated that histamine induces scratching behavior in ICR mice through both histamine H1 and H2 receptors, and that histamine plays a major role in passive cutaneous anaphylaxis-induced scratching behavior. Histamine might also play an important role in compound 48/80-induced scratching behavior.     

Effect of Lo Han Kuo (Siraitia grosvenori Swingle) on nasal rubbing and scratching behavior in ICR mice

We studied the effect of Lo Han Kuo (Siraitia grosvenori Swingle) on histamine-induced nasal rubbing and compound 48/80-induced skin scratching behavior in ICR mice. An extract and glycoside (a complex of sweet components) of Lo Han Kuo were used in the study. Both the extract and glycoside caused no significant effect on nasal rubbing or scratching behavior, even at a dose of 1000 mg/kg when administered in a single dose. However, the effect of Lo Han Kuo became clear after repeated administration, and 300 and 1000 mg/kg of both extract and glycoside significantly inhibited nasal rubbing and skin scratching behavior after consecutive treatment for 4 weeks. Both the extract and glycoside inhibited the histamine release induced by compound 48/80 at concentrations of 300 and 1000 microg/ml. From these results, it is assumed that the inhibition of nasal rubbing and skin scratching behavior induced by Lo Han Kuo occurs through a mast cell-dependent mechanism.     

Inhibitory effects of Moutan cortex on immediate allergic reactions

The anti-allergic effect of an ethanol extract from Moutan Cortex was evaluated in some animal models. The Moutan Cortex extract (30, 100 mg/kg, i.p.) dose-dependently inhibited systemic anaphylactic shock induced by compound 48/80 in mice. It also inhibited dose-dependently the scratching behavior induced by compound 48/80 or histamine at a dose of 100 mg/kg. An increase in the vascular permeability induced by compound 48/80 or histamine was also inhibited by the Moutan Cortex. In addition, in vitro studies, the Moutan Cortex inhibited histamine release from rat peritoneal mast cells induced by compound 48/80. To investigate the active component of Moutan Cortex extract, it was suspended in water and extracted with EtOAc to yield EtOAc insoluble (A) and soluble (B) fractions. The effect of extract (B) was more potent than that of extract (A) in inhibiting histamine release. From these findings, it seems likely that the Moutan Cortex extract is effective in antagonizing certain pharmacological effects induced by compound 48/80, which is probably mediated by inhibiting the release of histamine from mast cells and antagonizing the effect on histamine. The main active component of Moutan Cortex is considered to be contained in extract (B). In conclusion, Moutan Cortex may be useful for the relief of symptoms of atopic dermatitis and other allergy-related diseases.     

Antipruritic effect of ginsenoside rb1 and compound k in scratching behavior mouse models

The antipruritic and vascular permeability-inhibitory effects of ginsenoside Rb1, a main component of ginseng frequently used as a traditional medicine in Asian countries, and its metabolite compound K by intestinal microflora were investigated in scratching behavior animal models induced by compound 48/80, substance P, and histamine. Ginsenoside Rb1 and compound K orally administered 1 and 6 h before the treatment of compound 48/80 showed antipruritic effect. These ginsenosides administered at a dose of 50 mg/kg 6 h before the treatment of compound 48/80 inhibited scratching behaviors by 51% and 64%, respectively, compared with that of the control. These ginsenosides also inhibited the vascular permeability of skin. Compound K intraperitoneally administered 1 h before the treatment of compound 48/80 potently inhibited the scratching behaviors induced by compound 48/80. However, intraperitoneally administered ginsenoside Rb1 did not inhibit scratching behaviors. Compound K inhibited compound 48/80-, substance P-, and histamine-induced scratching behaviors, with 50% inhibitory doses of 4.2, 5.9, and 3.8 mg/kg, respectively, and vascular permeability, with 50% inhibitory doses of 5.8, 6.8, and 4.1 mg/kg, respectively. These results suggest that ginsenoside Rb1 and its metabolite compound K by intestinal microflora can improve scratching behaviors.     

Involvement of unique mechanisms in the induction of scratching behavior in BALB/c mice by compound 48/80

Compound 48/80 induced scratching behavior in BALB/c mice, and the role of mast cell mediators in this behavior was examined. Mouse scratching behavior was detected and evaluated using a new apparatus, MicroAct. Compound 48/80 increased the incidence of scratching behavior and scratching time in a dose-dependent manner, accompanied by a potent activation of mast cells and a potent increase in vascular permeability. Dibucaine and mu-opioid receptor antagonists inhibited the scratching behavior. Although histamine H(1) receptor antagonists potently inhibited the vascular permeability increase, they did not affect the scratching behavior. Methysergide inhibited the scratching behavior slightly without affecting the vascular permeability increase, whereas cyproheptadine inhibited both. A cyclooxygenase inhibitor, a 5-lipoxygenase-activating protein inhibitor and a PAF receptor antagonist did not affect the scratching behavior. High doses of serotonin induced scratching behavior less frequently than did compound 48/80. Furthermore, mast cell-deficient WBB6F1-W/W(v) mice exhibited frequent scratching behavior after injection of compound 48/80. These results clearly indicate that compound 48/80 can induce scratching behavior in mice independent of mast cell mediators.     

Pentacyclic triterpenoids, alpha,beta-amyrins, suppress the scratching behavior in a mouse model of pruritus

In the search for natural compounds useful against pruritus, alpha,beta-amyrins, the pentacyclic triterpenes isolated from the resin of popular medicinal plant Protium heptaphyllum were examined on scratching behavior induced by dextran T40 and compound 48/80 in mice. The animals were pretreated orally with alpha,beta-amyrins (50, 100 and 200 mg/kg) or cyproheptadine (10 mg/kg), an antagonist of histamine and serotonin receptors and 2 h later, they were given subcutaneous injections of dextran T40 (75 mg/kg) or compound 48/80 (3 mg/kg) into the rostral back, and scratching was quantified for 20 min. The scratching behavior induced by dextran T40 and compound 48/80 was significantly inhibited in mice pretreated with alpha,beta-amyrins (100 and 200 mg/kg) or cyproheptadine (10 mg/kg), In addition, the compound 48/80-elicited degranulation of rat peritoneal mast cells (ex vivo) was also markedly reduced in animals pretreated with alpha,beta-amyrins (100 mg/kg) or ketotifen (1 mg/kg), a known mast cell stabilizer. In the open-field test, alpha,beta-amyrins (100 and 200 mg/kg)-pretreated mice showed no impairment of spontaneous locomotion, suggesting that these triterpenoids possess no sedative activity that could account for suppression of scratching behavior. These results clearly indicate the antipruritic effect of alpha,beta-amyrins and suggest that this effect may be related to a stabilizing action on mast cell membrane.     

Topical application of luteolin inhibits scratching behavior associated with allergic cutaneous reaction in mice

The present study is aimed at evaluating the effects of luteolin on the scratching behavior associated with an allergic cutaneous reaction in mice. Elicitation of passive cutaneous anaphylaxis, and intradermal injections of compound 48/80, histamine or serotonin induced scratching behavior in ICR mice. Models of irritant contact dermatitis and allergic contact dermatitis were prepared by the topical application of 2,4-dinitrochlorobenzene (DNCB) on the ears of mice. Topical application of luteolin at concentrations of 20 and 100 mug/site significantly inhibited the number of scratching incidents associated with passive cutaneous anaphylaxis, and a similar tendency was also observed in histamine-, serotonin- and compound 48/80-evoked cutaneous reactions. The vascular permeability increase induced by passive cutaneous anaphylaxis or histamine injection was also significantly reduced by luteolin. Luteolin showed a potent inhibition on the ear thickness increase in models of irritant contact dermatitis and allergic contact dermatitis. In conclusion, luteolin significantly inhibited the scratching behavior associated with allergic cutaneous anaphylaxis. Its effects against pruritus are mainly attributed to its inhibition of mediator release from activated mast cells and direct antagonist effects on the released mediators which may act as local pruritogens.     

Antiallergic and anti-inflammatory properties of the ethanolic extract from Gleditsia sinensis

This study was carried out to determine the effects of the 70% ethanolic extract from the anomalous fruits of Gleditsia sinensis LAM. (AFGS) on experimental allergic reactions and inflammation. AFGS (200, 500, 1000 mg/kg, p.o.) dose-dependently inhibited the systemic anaphylactic shock induced by compound 48/80 in mice and cutaneous reactions induced by histamine or serotonin in rats. At doses of 500 and 1000 mg/kg, AFGS showed a clear inhibition on homologous passive cutaneous anaphylaxis in rats. In vitro, AFGS significantly reduced histamine release from rat peritoneal mast cells triggered by compound 48/80 at concentrations of 20 and 50 micro/ml. Moreover, AFGS (500, 1000 mg/kg, p.o.) showed a significant inhibition on the hind paw edema in rats and ear swelling in mice caused by carrageenin and croton oil, respectively. It also clearly inhibited the vascular permeability induced by acetic acid in mice at a dose of 1000 mg/kg. These findings demonstrate that the ethanolic extract from the anomalous fruits of Gleditsia sinensis possesses antiallergic and anti-inflammatory activities, which may be mediated by reducing the release of mediators such as histamine from mast cells and weakening the inflammatory action of these mediators.     

Antipruritic effect of Cnidii Monnieri Fructus (fruits of Cnidium monnieri CUSSON)

Antipruritic effects of 70% ethanol extract (CM-ext) of Cnidii Monnieri Fructus (dried fruits of Cnidium monnieri CUSSON, Umberifferae) were investigated. In mice, an oral administration of CM-ext (200 and 500 mg/kg) inhibited compound 48/80-induced scratching behavior without influence on spontaneous locomotion. Isopimpinellin (3) and osthol (1), coumarin derivatives isolated from CM-ext, showed an inhibitory effect on compound 48/80-induced scratching behavior.     

Potent pruritogenic action of tryptase mediated by PAR-2 receptor and its involvement in anti-pruritic effect of nafamostat mesilate in mice

The pruritogenic potency of tryptase and its involvement in anti-pruritic effect of intravenous nafamostat mesilate (NFM) were studied in mice. An intradermal injection of tryptase (0.05-1 ng/site) elicited scratching in ICR mice, while chymase was without effects at doses of 0.05-50 ng/site. The dose-response curve of tryptase action was bell-shaped and the effect peaked at 0.1 ng/site (approximately 0.7 fmol/site). NFM (10 mg/kg) inhibited scratching induced by tryptase but not by histamine and serotonin. NFM (1-10 mg/kg) produced the dose-dependent inhibition of scratching induced by intradermal compound 48/80 (10 microg/site). The inhibition by NFM (10 mg/kg) was abolished in mast cell-deficient (WBB6F1 W/W(V)) mice, but not in wild-type (WBB6F1 +/+) mice. NFM (10 mg/kg) suppressed tryptase activity in the mouse skin. Proteinase-activated receptor-2 (PAR-2) neutralizing antibody (0.1 and 1 microg/site) and the PAR-2 antagonist FSLLRY (10 and 100 microg/site) inhibited scratching induced by tryptase (0.1 ng/site) and compound 48/80 (10 microg/site). These results suggest that mast cell tryptase elicits itch through PAR-2 receptor and that NFM inhibits itch-associated responses mainly through the inhibition of mast cell tryptase.     

Antipruritic and antiinflammatory effects of aqueous extract from Si-Wu-Tang

Si-Wu-Tang (SWT), a traditional Chinese formula, has been clinically used in the treatment of cutaneous pruritus, chronic inflammation, and other diseases. The present study was carried out to observe the antipruritic and antiinflammatory effects of SWT aqueous extract using compound 48/80 and picryl chloride (PC) models in mice. SWT (500, 1000 mg/kg p.o.) clearly reduced the scratching responses elicited by compound 48/80 in normal mice. At doses of 250 and 500 mg/kg, it inhibited the scratching responses induced by PC in mice actively sensitized with 2,4-dinitrophenol (DNP)-ovalbumin (OVA) plus alum. Furthermore, SWT (250, 500, 1000 mg/kg) significantly inhibited the footpad swelling caused by compound 48/80 in mice. In the biphasic ear skin reactions induced by PC in actively sensitized mice, SWT (250, 500 mg/kg) reduced the immediate-phase reaction, but did not affect the late-phase reaction. In vitro, SWT (50-500 microg/ml) showed a concentration-dependent inhibition of the histamine release induced by compound 48/80 from rat peritoneal mast cells. The crude drugs contained in SWT, Paeoniae Radix (25, 100 microg/ml), Rehmanniae Radix, and Chuanxiong Rhizoma (100 microg/ml), also showed a clear inhibition, but Angelica Radix did not at the concentrations examined. These findings indicate that SWT aqueous extract has antipruritic and antiinflammatory effects in mice. SWT inhibits histamine release from rat mast cells, and Paeoniae Radix probably plays a crucial role in the formula.     

Characteristics of scratching behavior induced by some chemical mediators in hairless mice

To find the characteristics of scratching behavior in hairless mice (HR-1), compound 48/80 and some putative chemical mediators of allergic reaction were injected intradermally into the backs of mice, and the number of scratching behaviors was measured. As reference mice, NC/Nga, ICR, and ddY mice were used. Scratching behavior in HR-1 and ICR mice was increased dose-dependently by compound 48/80. The same result was also observed with NC/Nga and ddY mice. However, the response in NC/Nga and ddY mice was far less than those of HR-1 and ICR mice. Similar to NC/Nga and ddY mice, HR-1 mice showed less sensitivity to histamine than ICR mice. On the other hand, the HR-1 mice showed a high response to serotonin compared with those of the NC/Nga and ddY mice. The scratching behavior in HR-1 mice induced by substance P was increased, but the effect was less potent than those in NC/Nga, ICR, and ddY mice. These results suggest that the scratching behavior induced by compound 48/80 in HR-1 mice is mainly attributable to serotonin.     

Evaluation of antipruritic effects of red ginseng and its ingredients in mice

The anti-pruritic effect of red ginseng (the steamed root of Panax ginseng C.A. Meyer, Araliaceae), a traditional medicine in Asian countries, was investigated in mouse scratching behavior models induced by either compound 48/80 or histamine. Red ginseng and its saponin fraction, but not its polysaccharide fraction, showed an anti-pruritic effect. Representative constituents in the saponin fraction, ginsenosides Rg3 and Rh2, inhibited scratching behavior and vascular permeability. These ginsenosides also inhibited the expression of TNF-alpha and IL-4 induced by IgE-antigen complex in RBL-2H3 cells, as well as acetic acid-induced writhing in mice. These results suggest that red ginseng and its ingredients, ginsenosides Rg3 and Rh2, may inhibit scratching behavior by inhibiting IL-4 and TNF-alpha expression, promoting membrane stability, and inhibiting Ca (++) influx.     

Inhibition of immediate allergic reactions by ethanol extract from Plumbago zeylanica stems

The antiallergic properties of the 70% ethanol extract from Plumbago zeylanica stems (EPZ) were investigated in the present study. The extract (500, 1000 mg/kg, p.o.) dose-dependently inhibited systemic anaphylactic shock induced by compound 48/80 in mice, reduced homologous passive cutaneous anaphylaxis and skin reactions induced by histamine or serotonin in rats, significant differences were observed at the dose of 1000 mg/kg. In vitro, EPZ (5, 20, 50 microg/ml) concentration-dependently reduced histamine release from rat peritoneal mast cells caused by compound 48/80 and antigen. EPZ (50 microg/ml) markedly increased intracellular cAMP content of rat mast cells. These findings demonstrate that EPZ inhibits mast cell-dependent immediate allergic reactions, which is probably mediated by reducing the release of mediators such as histamine from mast cells via elevating intracellular cAMP level and weakening the inflammatory action of mediators.     

Analysis of the factor(s) involved in pathogenesis of zymosan-induced inflammation in rats

The role of mast cell degranulation in increased vascular permeability in zymosan-air-pouch inflammation, an experimental model of inflammation induced by zymosan in rats, was investigated. The complement in the inflammatory pouch fluid was exhausted, and mast cells in the pouch wall subcutaneous tissues were degranulated. The histamine level in the pouch fluid was elevated immediately after application of zymosan in the preformed air-pouch and then quickly declined. Plasma exudation into the pouch fluid changed in close parallel with the change of histamine level. Application of compound 48/80 in the air-pouch also brought about liberation of histamine from mast cells, accompanied with elevation of vascular permeability similar to that observed in the zymosan-air-pouch inflammation. However, the amount of the plasma exudation in the zymosan-air-pouch inflammation was about twice as high as that induced by compound 48/80, though the quantity of histamine liberated in the two cases was almost equal. Rats depleted of histamine and serotonin were incapable of responding to compound 48/80, but zymosan still induced increased vascular permeability. A combination treatment with pyrilamine and methysergide did not abolish plasma exudation caused by zymosan, but brought about complete blockade of the vascular permeability response to compound 48/80. These results suggest that some mechanisms independent of degranulation of mast cells are responsible in part for the initial sudden elevation of vascular permeability in zymosan-induced inflammation.     

12-Acetoxyhawtriwaic acid lactone, a diterpene from Egletes viscosa, attenuates capsaicin-induced ear edema and hindpaw nociception in mice: possible mechanisms

The diterpene, 12-acetoxyhawtriwaic acid lactone (AHAL, tanabalin) isolated from the flower buds of Egletes viscosa Less. (Asteraceae) was evaluated on capsaicin-induced ear edema and hindpaw nociception in mice. AHAL (12.5, 25 and 50 mg/kg, P. O.) significantly attenuated the ear edema response to topically applied capsaicin (250 microg), in a dose-related manner. At similar doses, AHAL also suppressed the nocifensive paw-licking behavior induced by intraplantar injection of capsaicin (1.6 microg). These responses to capsaicin were also greatly inhibited by ruthenium red (3 mg/kg, S. C.), a non-competitive capsaicin receptor (TRPV1) antagonist. The anti-edema effect of AHAL (50 mg/kg) seems unrelated to either blockade of mast cell degranulation or to histamine and serotonin receptor antagonism since AHAL did not modify the paw edema response induced by intraplantar injections of compound 48/80, histamine or serotonin. However, the hindpaw edema induced by substance P and vascular permeability increase induced by intraperitoneal acetic acid were significantly suppressed by AHAL. The antinociceptive effect of AHAL (50 mg/kg) was unaffected by naloxone pretreatment but was significantly antagonized by theophylline and glibenclamide, the respective blockers of adenosine and K(ATP)-channels. AHAL (50 mg/kg, P. O.) did not impair the ambulation or motor coordination of mice in open-field and rota-rod tests. These data suggest that AHAL inhibits acute neurogenic inflammation possibly involving capsaicin-sensitive TRPV1-receptors, endogenous adenosine and ATP-sensitive potassium channels.     

Vascular permeability and vasodilation induced by the Loxosceles intermedia venom in rats: involvement of mast cell degranulation, histamine and 5-HT receptors.

The mechanisms involved in both local and systemic effects of Loxosceles intermedia (brown spider) venom (LIV) are still poorly understood. We show using rats treated with Evans blue dye (50 mg/kg, i.v.) that small doses of the LIV (0.1, 0.3, 1 and 3 microg/site) dose-dependently increase the vascular permeability in rats, an effect unchanged by indomethacin (5mg/kg, i.p.), atropine (1mg/kg, i.p.), HOE-140 (2mg/kg, s.c.) or SR140333 (0.3mg/kg, i.p.), but fully avoided by promethazine (15 mg/kg, i.p.), methysergide (2mg/kg, i.p.) and compound 48/80 (3mg/kg/day for 3 days). Addition of cumulative concentrations of LIV (0.1-5 microg) in phenylephrine-contracted aortic rings resulted in a partial ( approximately 40%) and endothelium-dependent relaxation, inhibited by the nitric oxide synthase inhibitors L-NAME (10 microM) and L-NMMA (1mM), and the guanylate cyclase inhibitors methylene blue (100 microM) and ODQ (10 microM). LIV-induced relaxation was abolished by compound 48/80 (10 microM) and pyrilamine (a selective histamine H1 receptor antagonist; 100 microM), but not by atropine (1 microM) and indomethacin (10 microM). Our results disclose that LIV increases vascular permeability and induces vascular relaxation. These effects occur due to its ability to degranulate mast cells and release mediators such as histamine and serotonin.     

Endogenous glucocorticoids inhibit scratching behavior induced by the administration of compound 48/80 in mice

In this study, we investigated the effects of endogenous glucocorticoids on the compound 48/80 (a condensation product of N-methyl-p-methoxyphenethylamine with formaldehyde)-induced mouse scratching behavior using either RU-486 (mifepristone), a glucocorticoid receptor antagonist, or a surgical resection of the adrenal glands. Subcutaneous injection of compound 48/80 induced not only a corticosterone elevation in the plasma but also an enhanced expression of corticotropin releasing hormone (CRH) mRNA in the paraventricular nucleus, which thus suggests that hypothalamic-pituitary-adrenal axis is activated by the compound 48/80-induced cutaneous reaction. Inhibition of such an endogenous glucocorticoid activity by RU-486 significantly increased the degree of scratching behavior at not only the early-phase (<60 min) but also the late-phase (>60 min) time course after the injection of compound 48/80. Since the elevation of the histamine levels in the plasma in the RU-486-treated mice was no longer found in late-phase scratching behavior, these results thus indicate that histamine is a dominant mediator responsible for early-phase scratching behavior, while different mediators other than histamine may be also involved in the induction of late-phase scratching behavior. Moreover, surgical removal of adrenal glands also significantly increased the compound 48/80-induced scratching behavior without affecting anxiety and locomotor parameters, indicating that endogenous glucocorticoids exert their anti-pururitogenic effects independently of changes in behavioral performance. In conclusion, endogenous glucocorticoid activity was found to suppress the compound 48/80-induced scratching behavior in mice.