Kraft Tamar T, Huang Donald, Lolier Melanie, Warshaw Deena, LaMagna Sam, Natanova Elona, Sclafani Anthony, Bodnar Richard J
Behavioral and Cognitive Neuroscience Cluster of the Psychology Doctoral Program, The Graduate Center, City University of New York, New York, NY, USA.
Department of Psychology, Queens College, City University of New York, New York, NY, USA.
Pharmacol Biochem Behav. 2016 Sep;148:76-83. doi: 10.1016/j.pbb.2016.06.007. Epub 2016 Jun 16.
Conditioned flavor preferences (CFP) are elicited by sucrose and fructose relative to saccharin in rats and inbred mice. Whereas dopamine, but not opioid receptor antagonists interfere with the acquisition (learning) and expression (maintenance) of sugar-CFP in rats, these antagonists differentially affect acquisition and expression of sucrose- and fructose-CFP in BALB/c and SWR inbred mice. Given that NMDA receptor antagonism with MK-801 blocks acquisition, but not expression of fructose-CFP in rats, the present study examined whether MK-801 altered the expression and acquisition of sucrose- and fructose-CFP in BALB/c and SWR mice. In expression experiments, food-restricted mice alternately consumed a flavored (CS+, e.g., cherry, 5 sessions) 16% sucrose or 8% fructose+0.2% saccharin solution and a differently-flavored (CS-, e.g., grape, 5 sessions) 0.2% saccharin solution. 2-Bottle CS choice tests occurred following vehicle or MK-801 at doses of 100 or 200μg/kg. MK-801 mildly reduced the magnitude of the expression of sucrose- and fructose-CFP in BALB/c mice, and blocked the expression of fructose-, but not sucrose-CFP at the high dose in SWR mice. In acquisition experiments, groups of BALB/c (0, 100μg/kg) and SWR (0, 100, 200μg/kg) mice were treated prior to acquisition training sessions that was followed by 2-bottle CS choice tests without injections. MK-801 (100μg/kg) eliminated acquisition of sucrose- and fructose-CFP in BALB/c, but not SWR mice. The 200μg/kg MK-801 dose eliminated acquisition of sucrose- and fructose-CFP in SWR mice. Thus, NMDA receptor signaling is essential for the learning of both forms of sugar-CFP in both strains with BALB/c mice more sensitive to MK-801 dose effects.
在大鼠和近交系小鼠中，相对于糖精，蔗糖和果糖会引发条件性味觉偏好（CFP）。虽然多巴胺而非阿片受体拮抗剂会干扰大鼠中糖-CFP的获得（学习）和表达（维持），但这些拮抗剂对BALB/c和SWR近交系小鼠中蔗糖-和果糖-CFP的获得和表达有不同影响。鉴于用MK-801拮抗NMDA受体会阻断大鼠中果糖-CFP的获得，但不影响其表达，本研究检测了MK-801是否会改变BALB/c和SWR小鼠中蔗糖-和果糖-CFP的表达及获得。在表达实验中，食物受限的小鼠交替饮用一种加味（条件刺激物+，如樱桃，5个疗程）的16%蔗糖或8%果糖+0.2%糖精溶液，以及一种不同味道（条件刺激物-，如葡萄，5个疗程）的0.2%糖精溶液。在给予100或200μg/kg剂量的溶剂或MK-801后进行双瓶条件刺激物选择测试。MK-801轻微降低了BALB/c小鼠中蔗糖-和果糖-CFP的表达程度，并且在高剂量时阻断了SWR小鼠中果糖-CFP的表达，但未阻断蔗糖-CFP的表达。在获得实验中，对BALB/c（0,100μg/kg）和SWR（0,100,200μg/kg）小鼠组在获得训练疗程前进行处理，随后进行不注射的双瓶条件刺激物选择测试。MK-801（100μg/kg）消除了BALB/c小鼠中蔗糖-和果糖-CFP的获得，但未消除SWR小鼠中的获得。200μg/kg剂量的MK-801消除了SWR小鼠中蔗糖-和果糖-CFP的获得。因此，NMDA受体信号传导对于两种品系中两种形式的糖-CFP的学习都是必不可少的，其中BALB/c小鼠对MK-801剂量效应更敏感。
