Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2021 Jul;207(4):479-495. doi: 10.1007/s00359-021-01491-5. Epub 2021 May 30.
Taste aversion learning is universal. In animals, a single presentation of a novel food substance followed hours later by visceral illness causes animals to avoid that taste. This is known as bait-shyness or the Garcia effect. Humans demonstrate this by avoiding a certain food following the development of nausea after ingesting that food ('Sauce Bearnaise effect'). Here, we show that the pond snail Lymnaea stagnalis is capable of the Garcia effect. A single 'pairing' of a novel taste, a carrot slurry followed hours later by a heat shock stressor (HS) is sufficient to suppress feeding response elicited by carrot for at least 24 h. Other food tastes are not suppressed. If snails had previously been exposed to carrot as their food source, the Garcia-like effect does not occur when carrot is 'paired' with the HS. The HS up-regulates two heat shock proteins (HSPs), HSP70 and HSP40. Blocking the up-regulation of the HSPs by a flavonoid, quercetin, before the heat shock, prevented the Garcia effect in the snails. Finally, we found that snails exhibit Garcia effect following a period of food deprivation but the long-term memory (LTM) phenotype can be observed only if the animals are tested in a food satiated state.
味觉厌恶学习是普遍存在的。在动物中，单一呈现一种新的食物物质，数小时后再出现内脏疾病，会导致动物避免这种味道。这被称为诱饵回避或加西亚效应。人类通过在摄入某种食物后出现恶心来避免某种食物（“贝纳酱汁效应”），从而表现出这种现象。在这里，我们证明了田螺是能够产生加西亚效应的。单一的“配对”，即胡萝卜泥，数小时后再加上热休克应激源（HS），足以抑制至少 24 小时内对胡萝卜的进食反应。其他食物的味道不会被抑制。如果田螺以前曾以胡萝卜作为食物来源，那么当胡萝卜与 HS“配对”时，就不会出现类似加西亚的效应。HS 上调了两种热休克蛋白（HSPs），HSP70 和 HSP40。在热休克之前，用一种黄酮类化合物槲皮素阻断 HSP 的上调，可以防止田螺产生加西亚效应。最后，我们发现，田螺在经历一段时间的食物剥夺后会产生加西亚效应，但只有在动物处于饱食状态下进行测试时，才能观察到长期记忆（LTM）表型。
