Jpn. J. Pharmacol. 81 (3), 313 - 315 (1999)

Antagonistic Effect of N-Methyltyramine on 2-Adrenoceptor
in Mice

Hirofumi Koda1, Yoshiaki Yokoo2, Nobuya Matsumoto2, Yoshihide Suwa1, Hirotatsu Fukazawa3,
Hitoshi Ishida3, Kuniro Tsuji3, Haruo Nukaya3 and Kinya Kuriyama4

1Products Safety & Alcohol Science Laboratory, Suntory Limited, 1 - 1 - 1, Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka 618 - 8503, Japan
2Technical Development Department, Suntory Limited, 5 - 2 - 5, Yamazaki, Shimamoto-cho, Mishima-gun, Osaka 618 - 0001, Japan
3Department of Medicinal Chemistry of Natural Product, School of Pharmaceutical Science, University of Shizuoka,
52 - 1, Yada, Shizuoka 422 - 8526, Japan
4Kyoto Prefectural University of Medicine, Hirokoji, Kawaramachi-tori, Kamigyou-ku, Kyoto 602 - 8566, Japan

Abstract: We examined the effect of N-methyltyramine (NMT) on 2-adrenoceptor. NMT (10-8 -
10-3 M) inhibited the binding of [3H]p-aminoclonidine to 2-adrenoceptor dose-dependently. However, the IC50 value for NMT (5.53~10-6 M) was higher than that for RX821002, an 2-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 2-adrenoceptor antagonist. However, the affinity of NMT for 2-adrenoceptor is weaker than that of RX821002.

Keywords: N-Methyltyramine, 2-Adrenoceptor, Scopolamine

Copyright The Japanese Pharmacological Society 1999

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