【摘要】 本文报道了四氢异喹啉生物碱（TIQ）:左旋千金藤啶碱（1—SPD）,左旋及消旋四氢巴马汀（THP）及小檗胺（BBM）对大鼠脑内DA₂,5-HT₂及β—肾上腺素受体的结合特性。 所测的四种TIQ对β-肾上腺素受体的亲和力均很低(IC₅₀大于10^-4M)。结果表明,THP对单胺能神经递质受体亲和力远小于经典的单胺受体阻断剂,从而提示单胺受体阻断可能并非THP影响单胺能神经传递的主要机制。作者认为THP一类的TIQ,生物碱至少可以通过两种机制发挥作用:单胺受体阻断及利血平样“颗粒效应”。而对于THP,起主要作用的是引起单胺排空的“颗粒效应”。此外,实验中发现1-SPD与DA₂受体结合并不是简单的双分子反应,表现为1-SPD/[³H]螺环哌啶酮抑制曲线的Hill系数远小于1。这一受体结合特点可能与其在动物行为实验中表现出的部分激动剂性质有关。更多还原

【Abstract】 Four tetrahydroisoquinoline (TIQ) alkaloids, 1-stepholidine(SPD), 1-and dl-tatrahydropalmatine ( THP ) , berbamine( BBM ) have been investigated for their in vitro affinities to ratbrain DA2, 5-HT2 and betaadrenergic receptors. The rank orderof their potencies (IC50) on DA2 receptors is : 1-SPD(2.3×10-7M)> 1-THP (1.56×10-6M)>dl-THP ( 2.52 ×10-6M ) > BBM ( 1.22 ×10-5M) and that on 5-HT2 receptors is:1-THP ( 8.25×10-6M )>1 -SPD (1.74×10-5M) >dl-THP ( 2.2 ×10-5M ) >BBM (4 .31 ×10-5M).Their affinities for betaadrenergic receptors are very low, IC50sbeing more than 10-4M.It seems that the receptor blockingeffect may not be the main mechanism underlying the central effectof THP and several structurally related compounds which depletmonoamine storage.In addition, 1 -SPD has been found to be an atypical DA2 antagonist which yields an shallow inhibition curve against ( 3H ) spiroperidol with a Hill coefficient less than unit.更多还原