豚鼠心房存在苯环立啶受体

EXISTENCE OF PHENCYCLIDNE RECEPTOR IN GUINEA PIG ATRIA

用氚标记苯环立啶（[^3H]-PCP)与豚鼠心房匀浆蛋白作受体结合试验。结果表明豚鼠心房具有与[^3H]-PCP相结合的部位，结合具有特异性、饱和性、可逆性和立体专一性。Scatchard分析。豚鼠心房有两个不同亲和力的特异结合部位；高亲和力和低亲和力结合部位，两者的解离常数Kd1和Kd2分别为12.15±0.414nmol/L和561.23±121.36nmol/L;最大结合Bmax1为0.71±0.029pmol/mg蛋白，Bmax2为1.047±0.099pmol/mg蛋白，竞争性抑制分析结果显示PCP受体和sigma受体的配基都可抑制[^3H]-PCP的结合，PCP受体的配基的抑制作用强于sigma配基，而广谱阿片激动剂埃托啡（etorphine)却无抑制作用，结果提示豚鼠心房存在PCP受体。豚鼠右心房的冰冻切片和[^3H]-PCP进行体外受体结合放射自显影，结果显示，在心房肌层有与[^3H]-PCP特异性结合部位，且呈比较均匀的散在分布。

[~3H]-PCP was used in receptor binding studies on membrane preparationfrom guinea pig atria.It was found that this binding was specific,saturable,re-versible and stereoselective.Scatchard plots revealed that guinea pig atria hadtwo different affinity binding sites.The high affinity constant(Kd_1)and low af-finity constant(Kd_2)were 12.15±0.414 nmol/1 and 561.23±121.36 nmol/1,respectively;the maximum bindings(B_(max))were 0.71±0.029 pmol/mg protein(B_(max1))and 1.047±0.099 pmol/mg protein(B_(max2)),respectively.The displace-ment analysis revealed that the [~3H]-PCP binding was inhibited by the ligands ofboth PCP and sigma receptors,white the inhibition of PCP ligands was larger thanof sigma ligands.Etorphine,an agonist of opioid receptors,failed to inhibit thebinding of [~3H]-PCP.The results mentioned above show the existence of a specificPCP receptor in guinea pig atria.The autoradiographic analysis of guinea pig right atria was shown that therewas autoradiographic localization of [~3H]-PCP on atria of guinea pig with homo-genous distribution,suggesting that the distribution of PCP receptor in atria washomogeneous relatively.