【摘要】 <正> 枳实有效成份之—N—甲基酪胺(简称 MT)能间接兴奋α和β受体而发挥升压作用。曾报道心得舒与 MT 对离体豚鼠心房和在体兔心的β受体有竞争性拮抗作用,证明 MT 作用于β受体而发挥强心作用。据文献报道β受体兴奋时血浆或组织的环腺苷酸(cAMP)含量增加,α受更多还原

【Abstract】 There is evidence that N-methyltyramine,an active principle of Zhishi,canstimulate the vascular α-and β-receptors indirectly.Studies were made to detectwhether or not the positive inotropie effect of N-methyltyramine was due to thestimulation of cardiac α-and β-receptors.Experiments on the isolated atrium of guinea pigs show that phentolamine canblock the positive inotropie effect of N-methyltyramine.Perfusion experiments on theisolated heart of guinea pigs prove that both phentolamine and propranolol can alsoblock the positive inotropie effect of N-methyltyramine.Further experiments involving measurements of cardiac cAMP and cGMP levelof mice or plasma cGMP level of rabbits demonstrate a significant increase in thesecyclic nueleotides after the administration of N-methyltyramine.The evidence thus obtained suggests that N-methyltyramine stimulates cardiac α-and β-receptors and its action is followed by the increase of cGMP and cAMPlevels respectively which in turn produce the positive inotropic effect.更多还原