Abstract：
BACKGROUND: Muscarinic receptor activity in the basolateral amygdala (BLA) is known to be involved in plasticity mechanisms that underlie emotional learning. The BLA is involved in the Attenuation of Neophobia, an incidental taste learning task in which a novel taste becomes familiar and recognized as safe.
OBJECTIVE: Here we assessed the role of muscarinic receptor activity in the BLA in incidental taste learning.
METHODS: Young adult male Wistar rats were bilaterally implanted with cannulas aimed at BLA. After recovery, rats were randomly assigned to either vehicle or muscarinic antagonist group, for each experiment. We tested the effect of specific and non-specific muscarinic antagonists administered either 1) 20 min before novel taste presentation; 2) immediately after novel taste presentation; 3) immediately after retrieval (the second taste presentation on Day 5 -S2-) or immediately after the fifth taste presentation on Day 8 (S5).
RESULTS: Non-specific muscarinic receptor antagonist scopolamine infused prior to novel taste, while not affecting novel taste preference, abolished AN, i.e., the increased preference observed in control animals on the second presentation. When administered after taste consumption, intra-BLA scopolamine not only prevented AN but caused a steep decrease in the taste preference on the second presentation. This scopolamine-induced taste avoidance was not dependent on taste novelty, nor did it generalize to another novel taste. Targeting putative postsynaptic muscarinic receptors with specific M1 or M3 antagonists appeared to produce a partial taste avoidance, while M2 antagonism had no effect.
CONCLUSIONS: These data suggest that if a salient gustatory experience is followed by muscarinic receptors antagonism in the BLA, it will be strongly and persistently avoided in the future. The study also shows that scopolamine is not just an amnesic drug, and its cognitive effects may be highly dependent on the task and the structure involved.
OBJECTIVE: Here we assessed the role of muscarinic receptor activity in the BLA in incidental taste learning.
METHODS: Young adult male Wistar rats were bilaterally implanted with cannulas aimed at BLA. After recovery, rats were randomly assigned to either vehicle or muscarinic antagonist group, for each experiment. We tested the effect of specific and non-specific muscarinic antagonists administered either 1) 20 min before novel taste presentation; 2) immediately after novel taste presentation; 3) immediately after retrieval (the second taste presentation on Day 5 -S2-) or immediately after the fifth taste presentation on Day 8 (S5).
RESULTS: Non-specific muscarinic receptor antagonist scopolamine infused prior to novel taste, while not affecting novel taste preference, abolished AN, i.e., the increased preference observed in control animals on the second presentation. When administered after taste consumption, intra-BLA scopolamine not only prevented AN but caused a steep decrease in the taste preference on the second presentation. This scopolamine-induced taste avoidance was not dependent on taste novelty, nor did it generalize to another novel taste. Targeting putative postsynaptic muscarinic receptors with specific M1 or M3 antagonists appeared to produce a partial taste avoidance, while M2 antagonism had no effect.
CONCLUSIONS: These data suggest that if a salient gustatory experience is followed by muscarinic receptors antagonism in the BLA, it will be strongly and persistently avoided in the future. The study also shows that scopolamine is not just an amnesic drug, and its cognitive effects may be highly dependent on the task and the structure involved.
摘要：
背景：已知基底外侧杏仁核（BLA）中的毒蕈碱受体活性与情感学习的可塑性机制有关。BLA参与了新恐惧症的衰减，一种偶然的味觉学习任务，其中一种新颖的味觉变得熟悉并被认为是安全的。
目的：在这里，我们评估了BLA中毒蕈碱受体活性在偶然味觉学习中的作用。
方法：年轻成年雄性Wistar大鼠双侧植入针对BLA的插管。恢复后,大鼠被随机分配到媒介物或毒蕈碱拮抗剂组，每个实验我们测试了以下施用的特异性和非特异性毒蕈碱拮抗剂的效果:1)新味道呈现前20分钟;2)新味道呈现后立即;3)恢复后立即(第5天-S2-第二次味道呈现)或第8天第五次味道呈现后立即(S5)。
结果：在新味道之前注入非特异性毒蕈碱受体拮抗剂东莨菪碱，虽然不影响小说口味偏好，废除了AN,即，在第二次展示时，在对照动物中观察到的偏好增加。当食用后服用时，BLA内的东pol碱不仅可以预防AN，而且在第二次出现时导致味觉偏好急剧下降。这种东pol碱诱导的味觉回避不依赖于味觉新颖性，它也没有概括到另一种小说的味道。用特定的M1或M3拮抗剂靶向假定的突触后毒蕈碱受体似乎产生部分味觉回避，而M2拮抗作用没有影响。
结论：这些数据表明，如果在BLA中出现明显的味觉体验后出现毒蕈碱受体拮抗作用，今后将坚决避免。研究还表明，东pol碱不仅仅是一种失忆药物，其认知效果可能高度依赖于所涉及的任务和结构。
目的：在这里，我们评估了BLA中毒蕈碱受体活性在偶然味觉学习中的作用。
方法：年轻成年雄性Wistar大鼠双侧植入针对BLA的插管。恢复后,大鼠被随机分配到媒介物或毒蕈碱拮抗剂组，每个实验我们测试了以下施用的特异性和非特异性毒蕈碱拮抗剂的效果:1)新味道呈现前20分钟;2)新味道呈现后立即;3)恢复后立即(第5天-S2-第二次味道呈现)或第8天第五次味道呈现后立即(S5)。
结果：在新味道之前注入非特异性毒蕈碱受体拮抗剂东莨菪碱，虽然不影响小说口味偏好，废除了AN,即，在第二次展示时，在对照动物中观察到的偏好增加。当食用后服用时，BLA内的东pol碱不仅可以预防AN，而且在第二次出现时导致味觉偏好急剧下降。这种东pol碱诱导的味觉回避不依赖于味觉新颖性，它也没有概括到另一种小说的味道。用特定的M1或M3拮抗剂靶向假定的突触后毒蕈碱受体似乎产生部分味觉回避，而M2拮抗作用没有影响。
结论：这些数据表明，如果在BLA中出现明显的味觉体验后出现毒蕈碱受体拮抗作用，今后将坚决避免。研究还表明，东pol碱不仅仅是一种失忆药物，其认知效果可能高度依赖于所涉及的任务和结构。
