Hirokazu Kawasaki

Scratching Behavior in Various Strains of Mice

Scratching behavior was induced in 12 strains of mice and the frequency was compared. An injection of histamine at a dose of 50 nmol induced frequent scratching behavior only in ICR mice, although the same dose of serotonin induced frequent scratching behavior in all strains of mice except for A/J. Histamine (10 nmol), serotonin (1 nmol), substance P (50 nmol) and passive cutaneous anaphylaxis induced significant vascular permeability increase in BALB/c, ICR, ddY and NC/Nga mice. These four stimuli also induced frequent scratching behavior in ICR mice. However, they failed to induce substantial increase in the incidence of scratching in the other three strains, except for ddY, which exhibited a slight but significant increase against substance P injection. These results suggest that the ICR mouse is a good responder for scratching behavior against various stimuli, especially against histamine. Thus ICR mice may be suitable for studying mediators and/or mechanisms for itching.

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.

Anti-inflammatory and bronchodilator properties of KF19514, a phosphodiesterase 4 and 1 inhibitor.

We investigated the effects of KF19514 (5-phenyl-3-(3-pyridyl)methyl-3H-imidazo[4,5-c][1,8]naphthyridin-4 (5H)-one) on bronchoconstriction and allergic inflammation in guinea pigs and on tumor necrosis factor-alpha production in mice. KF19514 inhibited phosphodiesterase 4 (IC50 = 0.40 microM) and phosphodiesterase 1 (IC50 = 0.27 microM) derived from canine tracheal smooth muscles. KF19514 relaxed contracted tracheal smooth muscle and had a potent inhibitory effect on antigen-induced bronchoconstriction (EC50 = 0.058 microM) in vitro. Intravenous administration of KF19514 inhibited histamine-induced bronchoconstriction (ID50 = 2.8 microg/kg i.v.). Moreover, oral administration of KF19514 inhibited anaphylactic bronchoconstriction (ID50 = 0.2 mg/kg p.o.), and eosinophil infiltration in airway stimulated with platelet-activating factor (PAF) or antigen. KF19514 also produced a significant inhibition of tumor necrosis factor-alpha production in mice (ID50 = 0.023 mg/kg p.o.). Finally, KF19514 completely inhibited antigen-induced hyperreactivity at 0.1 mg/kg p.o. These results demonstrate that KF19514 may have efficacy in the treatment of asthma.

Evaluation of anti-scratch properties of oxatomide and epinastine in mice

Anti-scratch effects of oxatomide and epinastine were examined in mice. Scratching behavior and cutaneous reactions were induced in BALB/c, ICR and ddY mice by dinitrofluorobenzene painting, passive cutaneous anaphylaxis and substance P injection, respectively. Although oxatomide and epinastine failed to inhibit scratching behavior in BALB/c mice, they inhibited the cutaneous reaction significantly. The drugs potently inhibited both scratching behavior and cutaneous reaction in ICR mice. They also inhibited scratching behavior and cutaneous reaction in ddY mice, although cetirizine and terfenadine failed to affect them. Histamine did not induce frequent scratching behavior in BALB/c and ddY mice. These results indicate that oxatomide and epinastine inhibit the scratching behavior in ICR mice associated with passive cutaneous anaphylaxis mainly through an antagonistic action on histamine H(1) receptors. The results also indicate that these drugs inhibit substance P-induced scratching behavior in ddY mice through an action independent of the antagonistic action on histamine H(1) receptors.

Potentiation of antigen-induced histamine release from rat peritoneal mast cells through a direct interaction between mast cells and non-mast cells.

Rat peritoneal mast cells, which had been sensitized two days earlier by an intraperitoneal injection of rat monoclonal IgE antibodies, were purified by density gradient centrifugation with 60% Percoll (cell purity > 95%). Histamine release from the purified mast cells (PMC) was then compared to that of a non-purified preparation (peritoneal exudate cells; PEC). Both PEC and PMC released similar amounts of histamine upon stimulation with calcium ionophore A23187 and compound 48/80. In contrast, antigen-induced histamine release from PMC was very low compared to that of PEC. PEC released up to 30% of total histamine upon challenge with 1 microgram/ml of antigen, whereas histamine release from PMC was only one third or less than that of PEC. When PEC was suspended in 60% Percoll and treated for a period needed for purification, the reduction of antigen-induced histamine release was negligible. Mast cells purified by centrifugation on a metrizamide gradient released only small amount of histamine similar to Percoll-purified mast cells. Non-mast cells (NMC) recovered from the interface of the 60% Percoll potentiated the antigen-induced histamine release from PMC concentration- and time-dependently. The supernatant of the NMC suspension which was incubated at 37 degrees C for 60 min, however, failed to potentiate histamine release in PMC. We concluded therefore that separation media such as Percoll and metrizamide do not cause the low antigen-induced histamine release in PMC, but that the separation of mast cells from other cells present in the peritoneal cavity itself causes it. Antigen-induced mast cell histamine release is potentiated through a direct interaction between mast cells and NMC, and some cell surface molecules also seem to be involved.

Inhibition of Passive Cutaneous Anaphylaxis-associated Scratching Behavior by μ-Opioid Receptor Antagonists in ICR Mice.

Background: Itching in humans is attenuated by µ-opioid receptor antagonists. ICR mice display increases in scratching behavior upon induction of IgE-mediated passive cutaneous anaphylaxis (PCA), or intradermal injection of compound 48/80 or histamine. Methods: Cutaneous reactions were induced in ICR mice by IgE-mediated PCA, compound 48/80 and histamine, and the scratching behavior associated with the cutaneous reactions was evaluated. Results: Naloxone and nalmefene reduced the incidence of scratching behavior associated with PCA. Naloxone also inhibited the induction of scratching behavior caused by compound 48/80 and histamine. Naloxone did not affect the increase in vascular permeability caused by PCA and injection of compound 48/80. Conclusion: Scratching behavior in mice may be induced by a sensation or a mechanism similar to itching in humans and should become a useful model for examining itching in humans.

Characterization of antihistamines using biphasic cutaneous reaction in BALB/c mice

Effects of 11 histamine H1 receptor antagonists on IgE-mediated biphasic cutaneous reaction in mice were examined. The immediate phase reaction (IPR) assessed at 1 hour after antigen application was significantly inhibited by all antihistamines examined. The inhibition of IPR by cetirizine and mequitazine were potent, but those by cyproheptadine and diphenhydramine were weak. The later phase reaction (LPR) assessed at 24 hours after antigen application was inhibited by chlorpheniramine, oxatomide, ketotifen, mequitazine, emedastine, terfenadine and azelastine. The inhibition of LPR by emedastine was potent, but those by ketotifen and terfenadine were only partial. Emedastine inhibited both IPR and LPR comparably. Present results indicate that H1 receptor activation is involved in the IPR of the biphasic cutaneous reaction, and that the blockade of H1 receptors at IPR does not contribute to the attenuation of following LPR. Histamine H1 receptor antagonists inhibiting the LPR have a property distinct from H1 receptor antagonism, which may have an additional benefit for the treatment of allergic diseases.

CHARACTERIZATION OF PURIFICATION-ASSOCIATED REDUCTION IN IGE-DEPENDENT HISTAMINE RELEASE FROM RAT PERITONEAL MAST CELLS

Histamine release from purified rat peritoneal mast cells (PMC) was examined and compared to that from a non-purified preparation (PEC). Both PEC and PMC released similar amounts of histamine upon stimulation with compound 48/80, calcium ionophore A23187 and substance P. In contrast, IgE-dependent histamine release from PMC caused by antigen, anti-IgE and concanavalin A was very low compared to that of PEC. The reduced IgE-dependent histamine release from PMC, however, was recovered when PMC was reconstituted with non-mast cells (NMC) present in the peritoneal cavity. The effect was time-dependent and reached a plateau in 30 min. NMC from both sensitized and non-sensitized rats recovered the reduced histamine release from PMC dose-dependently. The potentiating effect of NMC was observed even in the presence of excess amount of phosphatidylserine. Supernatants of NMC and a mixture of PMC and NMC incubated for 1 hr at 37°C, however, failed to potentiate the histamine release. These results demonstrate that IgE-dependent histamine release from rat peritoneal mast cells is upregulated by other cells present in the peritoneal cavity, and that the mechanism involved is distinct from that of phosphatidylserine.

The effect of a TXA2 receptor antagonist ON-579 on experimental allergic reactions

The effect of a thromboxane A2 (TXA2) receptor antagonist, ON-579, on experimental allergic skin and airway reactions was studied in vivo. ON-579 at doses of 1 and 20 mg/kg clearly inhibited U-46619-induced increases in respiratory resistance (Rrs) in guinea pigs. ON-579 at doses of 1, 20 and 50 mg/kg inhibited the aerosolized antigen-induced biphasic increase in Rrs in guinea pigs. Moreover, ON-579 clearly inhibited repeated aeroantigen-induced airway hyperreactivity in guinea pigs. ON-579, however, did not have any significant effects on allergic cutaneous reactions in rats. These results suggest that ON-579 is a relatively selective TXA2 antagonist, especially in the airways, and indicate the efficacy of ON-579 on antigen-induced increase in airway resistance and antigen-induced airway hyperreactivity in guinea pigs.

Inhibitory Mechanisms of β-Adrenoceptor Agonists for Immunoglobulin E-mediated Experimental Allergic Reactions in Rats.

Inhibitory mechanisms of isoproterenol and clenbuterol for immunoglobulin E (IgE)-mediated experimental allergic reactions in rats were studied. IgE-mediated passive cutaneous anaphylaxis, histamine-induced cutaneous reaction and serotonin-induced cutaneous reaction were evoked at the same time in the same rats. Isoproterenol administered intravenously immediately before challenge inhibited all these reactions significantly. Clenbuterol administered intravenously 0-3 h before challenge also significantly inhibited the three cutaneous reactions. The inhibition was maximum when the drug was given 1 h before challenge. Passive cutaneous anaphylaxis was always inhibited more potently than histamine-induced cutaneous reaction and serotonin-induced cutaneous reaction by these beta-adrenoceptor agonists. Passive peritoneal anaphylaxis was caused by injecting an antigen intravenously. Isoproterenol administered intravenously immediately before challenge inhibited the reaction significantly. Clenbuterol administered intravenously 0-3 h before challenge also significantly inhibited passive peritoneal anaphylaxis, maximally so when given 1 h before challenge. In vitro IgE-dependent histamine release from sensitized peritoneal mast cells or mesenteric mast cells was not affected by isoproterenol and clenbuterol. Mouse monoclonal IgE, a foreign protein, administered intravenously decreased rapidly in the circulation. About 50% of the mouse IgE given disappeared in 20 min. The decrease of mouse IgE was partly but significantly inhibited by the beta-adrenoceptor agonists, and the inhibition was abolished by simultaneous treatment with propranolol. These results indicate that direct inhibition of mast cell activation does not contribute to the potent inhibition of in vivo allergic reactions in rats by beta-adrenoceptor agonists, and that inhibition of the allergic cutaneous reaction is partially explained by the inhibition of vascular permeability increases caused by mast cell mediators. Penetration of intravenously administered antigen from blood vessels to peripheral tissues to cause mast cell activation might be inhibited by beta-adrenoceptor agonists, and this could play some role in inhibiting intravenous antigen-induced allergic reactions in rats. Clenbuterol exhibited its maximum action with some latency in vivo, suggesting that some time-requiring process may be involved in the manifestation of its action.