大脑皮层~3H-三环哌酯结合位点的药理学特征

目的研究大脑皮层３Ｈ－三环哌酯（３Ｈ－ＴＣＰＮ）结合位点的药理学特征。方法在大鼠大脑皮层匀浆标本上，测定３Ｈ－ＴＣＰＮ的特异性结合位点以及药物对它的影响。结果３Ｈ－ＴＣＰＮ与大鼠大脑皮层膜标本具有特异性结合，其饱和性结合的参数与３Ｈ－ＱＮＢ的饱和性结合参数相似，其中，Ｋｄ值为０．４０ｎｍｏｌ·Ｌ－１，Ｂｍａｘ值为１２５８ｐｍｏｌ·ｇ－１。３Ｈ－ＴＣＰＮ特异性结合位点中，被阿托品取代的Ｍ受体部分占７０％，不被阿托品取代的称Ｘ位点部分占３０％；Ｘ结合位点既不为Ｎ受体激动剂烟碱和非竞争拮抗剂美加明所占据，也不为ＧＡＢＡ受体拮抗剂苦味毒素，甘氨酸受体拮抗剂士的宁和胆碱酯酶抑制剂毒扁豆碱所占据。结论大鼠大脑皮层３Ｈ－ＴＣＰＮ特异性结合位点中，７０％为Ｍ受体，其它位点的药理学性质有待进一步研究

Pharmacological profiles of 3H tricyclopinate hydrochloride binding sites in cerebral cortex

AIM To study the pharmacological profiles of 3H tricyclopinate hydrochloride (3H TCPN) binding sites in cerebral cortex. METHODS The specific binding of 3H TCPN and displacement of the drugs on the specific binding were determined in rat cerebral homogenates.RESULTS The specific binding of 3H TCPN in rat cerebral homogenates was saturable, the apparent dissociation constant value was 04 nmol·L-1. 70% of the 3H TCPN(10 nmol·L-1) specific binding could be displaced by atropine(1 μmol·L-1); the other 30% fractions could not be displaced by nicotinic receptor agonist nicotine, nicotinic receptor antagonist mecamylamine, GABA receptor antagonist picrotoxin, glycine receptor antagonist strychnine or cholinesterase inhibitor physostigmine at high concentration of 10 μmol·L-1. CONCLUSION The 70% of the 3H TCPN specific binding sites revealed muscarinic receptor profiles, but the pharmacological characteristics of the other 30% 3H TCPN specific binding sites remained to be further investigated.