Jpn. J. Pharmacol. 87 (2), 167-170 (2001)

Effects of Olopatadine Hydrochloride on the Cutaneous Vascular Hyperpermeability and the Scratching Behavior Induced by Poly-L-Arginine in Rats

Ken-ichi Hayashi*, Toshihiko Kaise, Kenji Ohmori, Akio Ishii and Akira Karasawa

Drug Development Research Laboratories, Pharmaceutical Research Institute, Kyowa Hakko Kogyo Co., Ltd., 1188 Shimotogari, Nagaizumi-cho, Sunto-gun, Shizuoka 411-8731, Japan

*Corresponding author. FAX: +81-559-86-7430

Abstract: Intradermal injections of poly-L-arginine induce cutaneous vascular hyperpermeability and scratching behavior in rats. Recently, we elucidated that the plasma extravasation involved both histamine and substance P, while the scratching behavior involved substance P, but not histamine. This study examined the effects of olopatadine hydrochloride (olopatadine), an antiallergic drug with histamine H₁-antagonistic action, on the poly-L-arginine-induced responses. Olopatadine (1 mg/kg, p.o.) significantly inhibited both the plasma extravasation and the scratching behavior, suggesting that its inhibitory effects are mediated by the suppression of neuropeptidergic action as well as histaminic action. Olopatadine seems to be a novel-type drug for the treatment of dermatitis.

Keywords: Cutaneous vascular hyperpermeability, Olopatadine hydrochloride, Scratching behavior

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