Papp M, Muscat R, Willner P
Department of Psychology, City of London Polytechnic, UK.
Psychopharmacology (Berl). 1993;110(1-2):152-8. doi: 10.1007/BF02246965.
Chronic exposure to very mild unpredictable stress has previously been found to reduce or abolish the acquisition of place preference conditioning. In the present study, chronic mild stress was found to abolish the acquisition of preferences for a distinctive environment paired with systemic administration of amphetamine (0.5 mg/kg) or quinpirole (100-400 micrograms/kg) or with quinpirole (0.75 micrograms) administered bilaterally within the nucleus accumbens. The locomotor stimulant effects of quinpirole (100-400 micrograms/kg) were also attenuated in stressed animals. The result suggest that decreased sensitivity to reward following chronic mild stress results from a decreased sensitivity of dopamine D2 receptors within the nucleus accumbens.
先前已发现，长期暴露于非常轻微的不可预测应激会降低或消除位置偏爱条件反射的习得。在本研究中，发现慢性轻度应激会消除对与全身注射苯丙胺（0.5毫克/千克）或喹吡罗（100 - 400微克/千克）配对的独特环境的偏爱习得，或消除对在伏隔核双侧注射喹吡罗（0.75微克）的独特环境的偏爱习得。喹吡罗（100 - 400微克/千克）对运动的刺激作用在应激动物中也减弱。结果表明，慢性轻度应激后对奖赏的敏感性降低是由于伏隔核内多巴胺D2受体的敏感性降低所致。
