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

摘要

References(12) Cited-By(4) 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.