Abstract—We studied the effect of a 2-week administration of cycloprolylglycine peptide (CPG) (1 and 2 mg/kg/day, i.p.) on the binding characteristics of serotonin 5-HT_2A-, NMDA-, metabotropic glutamate mGluII-, GABA_A- and GABA_B-receptors in the brain of inbred BALB/c mice in vitro and ex vivo. It was found that CPG at doses of 1 and 2 mg/kg/day reduces the density of 5-HT_2A receptors in the striatum of mice by 24 and 28%, respectively. A decrease in the density of NMDA receptors in the hippocampus was observed only at a dose of 2 mg/kg/day; it was 22%. At the same time, there was an increase in the density of GABA_A receptors in the frontal cortex at a dose of 1 mg/kg/day by 36% compared with the control. The 2-week administration of CPG at both doses did not affect B_max of mGluII- and GABA_B receptors, as well as K_d in all groups. In the in vitro radioligand assay, the CPG did not affect the specific binding of the labeled ligands of the studied receptors. These data indicate the functional involvement of 5-HT_2A, NMDA, and GABA_A receptors in the formation of the antidepressant-like effect of cycloprolylglycine in BALB/c mice for the first time.

中文翻译：

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血清素，谷氨酸和GABA受体参与环戊酰甘氨酸的抗抑郁样作用

摘要—我们研究了2周施用环丙脯氨酸甘氨酸肽（CPG）（1和2 mg / kg /天，腹腔注射）对5-羟色胺5-HT _2A -NMDA-代谢型谷氨酸mGluII-结合特性的影响，近交和离体BALB / c小鼠大脑中的GABA _A和GABA _B受体。发现以1和2mg / kg /天的剂量的CPG分别将小鼠纹状体中5-HT _2A受体的密度降低了24％和28％。仅在2 mg / kg /天的剂量下，观察到海马中NMDA受体的密度降低。是22％。同时，GABA _A的密度增加了1 mg / kg /天的剂量使额叶皮层中的受体比对照组高36％。两种剂量的CPG给药2周均未影响mGluII-和GABA _B受体的B _max以及所有组的K _d。在体外放射性配体测定中，CPG不会影响所研究受体的标记配体的特异性结合。这些数据表明5-HT _2A，NMDA和GABA _A受体的功能性参与首次在BALB / c小鼠中形成环脯氨酰甘氨酸的抗抑郁样作用。