Antagonistic Effect of N-Methyltyramine on α2-Adrenoceptor in Mice

Hirofumi Koda; Yoshiaki Yokoo; Nobuya Matsumoto; Yoshihide Suwa; Hirotatsu Fukazawa; Hitoshi Ishida; Kuniro Tsuji; Haruo Nukaya; Kinya Kuriyama

doi:10.1254/jjp.81.313

Short Communications

Antagonistic Effect of N-Methyltyramine on α₂-Adrenoceptor in Mice

Hirofumi Koda, Yoshiaki Yokoo, Nobuya Matsumoto, Yoshihide Suwa, Hirotatsu Fukazawa, Hitoshi Ishida, Kuniro Tsuji, Haruo Nukaya, Kinya Kuriyama

Author information

Hirofumi Koda
Products Safety & Alcohol Science Laboratory, Suntory Limited
Yoshiaki Yokoo
Technical Development Department, Suntory Limited
Nobuya Matsumoto
Technical Development Department, Suntory Limited
Yoshihide Suwa
Products Safety & Alcohol Science Laboratory, Suntory Limited
Hirotatsu Fukazawa
Department of Medicinal Chemistry of Natural Product, School of Pharmaceutical Science, University of Shizuoka
Hitoshi Ishida
Department of Medicinal Chemistry of Natural Product, School of Pharmaceutical Science, University of Shizuoka
Kuniro Tsuji
Department of Medicinal Chemistry of Natural Product, School of Pharmaceutical Science, University of Shizuoka
Haruo Nukaya
Department of Medicinal Chemistry of Natural Product, School of Pharmaceutical Science, University of Shizuoka
Kinya Kuriyama
Kyoto Prefectural University of Medicine

Keywords: N-Methyltyramine, α₂-Adrenoceptor, Scopolamine

JOURNAL FREE ACCESS

1999 Volume 81 Issue 3 Pages 313-315

DOI https://doi.org/10.1254/jjp.81.313

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Abstract

We examined the effect of N-methyltyramine (NMT) on α₂-adrenoceptor. NMT (10^-8 - 10^-3 M) inhibited the binding of [³H]p-aminoclonidine to α₂-adrenoceptor dose-dependently. However, the IC₅₀ value for NMT (5.53×10^-6 M) was higher than that for RX821002, an α₂-adrenoceptor antagonist (1.07×10^-8 M). RX821002 (5 mg/kg, i.p.) inhibited hypermotility induced by scopolamine (8 mg/kg, s.c.) in male ddY mice. NMT (20 or 100 mg/kg, i.p.) was found to have a dose-dependent inhibitory effect similar to that of RX821002. These findings indicate that NMT has the properties of an α₂-adrenoceptor antagonist. However, the affinity of NMT for α₂-adrenoceptor is weaker than that of RX821002.

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