The effects of chronic intranasal administration of cycloprolylglycine (CPG, 1 and 2 mg/kg) on the behavior of BALB/c and C57BL/6 mice and the brain neuroreceptor characteristics in BALB/c mice were studied. Intranasal administration of CPG (1 and 2 mg/kg, 2 weeks) to BALB/c mice in the Porsolt test resulted in a significant antidepressant-like effect more potent than that from intraperitoneal administration of CPG. At the same time, intranasal administration of CPG to C57BL/6 mice in the tail-suspension test was the same as that upon intraperitoneal administration and led to a moderate antidepressant-like effect (1 mg/kg, 4 weeks). Intranasal CPG did not produce any effect on anxiety or exploratory activity in the closed cross-maze test. Radioligand analyses showed an increased density of GABA_A receptors in the PFC (1 mg/kg) and reduced density of NMDAand 5HT_2A receptors in the hippocampus and striatum, respectively, after intranasal administration of CPG (1 and 2 mg/kg) for two weeks while not affecting mGluII receptor binding in the hippocampus. The significant difference in hippocampal NMDA binding between the two routes may indicate that this receptor is involved in the mechanism of the antidepressant-like effect of CPG.

研究了环丙甘氨酸（CPG，1 和 2 mg/kg）慢性鼻内给药对 BALB/c 和 C57BL/6 小鼠行为以及 BALB/c 小鼠脑神经受体特征的影响。在 Porsolt 试验中，向 BALB/c 小鼠鼻内施用 CPG（1 和 2 毫克/千克，2 周）导致显着的抗抑郁样作用比腹膜内施用 CPG 更有效。同时，C57BL/6小鼠尾部悬吊试验中CPG鼻内给药与腹腔给药相同，产生中等抗抑郁样作用（1mg/kg，4周）。在封闭的交叉迷宫测试中，鼻内 CPG 对焦虑或探索活动没有产生任何影响。放射性配体分析显示 GABA _{A 的}密度增加鼻内给予 CPG（1 和 2 毫克/千克）两周后，PFC 中的受体（1 毫克/千克）和海马和纹状体中 NMDA 和 5HT _2A受体的密度分别降低，同时不影响 mGluII 受体结合海马体。两种途径之间海马NMDA结合的显着差异可能表明该受体参与了CPG的抗抑郁样作用的机制。