Department of Psychology, East Tennessee State University, Department of Psychology, East Tennessee State University, 807 University Parkway, Box 70649, Johnson City, TN 37614, United States.
Behav Brain Res. 2013 Apr 1;242:102-9. doi: 10.1016/j.bbr.2012.12.037. Epub 2013 Jan 3.
Our laboratory has reported neonatal quinpirole (D(2)/D(3) agonist) treatment to rats increases dopamine D(2) receptor sensitivity that persists throughout the animal's lifetime. This model appears to have clinical relevance to schizophrenia, and smoking is common in this population. Male and female Sprague-dawley rats were neonatally treated with quinpirole from postnatal (P) days 1-21. After habituation from P30 to 32, animals were administered saline or nicotine (0.3, 0.5, or 0.7mg/kg free base) every other day from P33 to 49 and locomotor activity was assessed. Generally, animals neonatally treated with quinpirole and administered nicotine during adolescence demonstrated increased behavioral activity and/or sensitization compared to animals neonatally given saline and sensitized to nicotine as well as controls. However, animals neonatally treated with quinpirole and given the 0.7mg/kg dose of nicotine demonstrated elevated activity throughout testing but did not show sensitization, and only mild sex differences were reported. Therefore, microdialysis was performed on male rats sensitized to the 0.5mg/kg dose of nicotine, and results revealed that neonatal quinpirole sensitized dopamine overflow in response to nicotine to 500% above animals neonatally given saline and sensitized to nicotine at peak levels. In addition, neonatal quinpirole increased the accumbal BDNF in response to nicotine compared to all other groups, and nicotine alone also produced significant increases in striatal and accumbal BDNF. This study reveals that neonatal quinpirole enhanced adolescent nicotine sensitization, accumbal dopamine overflow, and BDNF protein in response to nicotine, which may be related to changes in the brain's reward system.
我们的实验室曾报道,新生期给予大鼠喹吡罗(D2/D3 激动剂)会增加多巴胺 D2 受体的敏感性,且这种敏感性会持续终生。该模型似乎与精神分裂症具有临床相关性,而该人群中吸烟较为普遍。新生期的雄性和雌性 Sprague-Dawley 大鼠从出生后(P)第 1-21 天接受喹吡罗处理。从 P30 到 P32 适应环境后,从 P33 到 P49 每隔一天给予动物生理盐水或尼古丁(0.3、0.5 或 0.7mg/kg 游离碱),并评估其运动活动。通常,与新生期给予生理盐水并对尼古丁产生敏化以及对照组的动物相比,新生期接受喹吡罗处理并在青春期给予尼古丁的动物表现出更高的行为活性和/或敏化。然而,与接受 0.7mg/kg 剂量尼古丁处理的动物相比,接受 0.5mg/kg 剂量尼古丁处理的动物在整个测试过程中表现出升高的活性但未表现出敏化,且仅报道了轻度的性别差异。因此,对对 0.5mg/kg 剂量尼古丁产生敏化的雄性大鼠进行微透析,结果显示,与新生期给予生理盐水并对尼古丁产生敏化的动物相比,新生期喹吡罗敏化了多巴胺对尼古丁的溢出,使其峰值增加 500%。此外,与所有其他组相比,新生期喹吡罗增加了对尼古丁的伏隔核 BDNF 反应,而尼古丁本身也显著增加了纹状体和伏隔核的 BDNF。本研究揭示了新生期喹吡罗增强了青春期尼古丁敏化、伏隔核多巴胺溢出和对尼古丁的 BDNF 蛋白反应,这可能与大脑奖励系统的变化有关。