Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada T2N 4N1.
J Exp Biol. 2012 Dec 15;215(Pt 24):4322-9. doi: 10.1242/jeb.075960. Epub 2012 Sep 12.
The pond snail, Lymnaea stagnalis, naturally inhabits slow flowing, shallow and stagnant environments in the northern temperate zone. Consequently, it will experience wide temperature fluctuations dependent on prevailing weather conditions. We hypothesize that periods of warming act as a thermal stressor to alter memory formation. Snails were exposed to an acute 1 h period of 30°C pond water and we determined how memory formation following operant conditioning of aerial respiration was affected. In the snails used here (Dutch strain), a single 0.5 h training session (TS) results in intermediate-term (3 h) but not long-term memory (LTM). Applying the thermal stressor during training caused memory enhancement (i.e. LTM lasting 24 h). However, the breathing rate also increased in warm water, which might explain the enhanced memory. Therefore, we applied the thermal stressor (1 h at 30°C) up to 4 h before or 1 h after training. This did not alter baseline breathing rate during the period when snails would experience training. However, the thermal stressor whether experienced prior to or following the single TS, resulted in an enhanced memory that persisted up to 48h (i.e. LTM). We conclude that memory enhancement is due to the stress associated with the thermal stimulus.
圆田螺，自然栖息于北方温带地区缓慢流动、浅而停滞的环境中。因此，它将经历广泛的温度波动，这取决于盛行的天气条件。我们假设变暖时期会对记忆形成产生热应激作用。蜗牛被暴露在 30°C 的池塘水中 1 小时的急性暴露期，我们确定了操作条件反射后空气呼吸的记忆形成是如何受到影响的。在这里使用的蜗牛（荷兰品系），单次 0.5 小时的训练课程（TS）会导致中期（3 小时）而不是长期记忆（LTM）。在训练期间施加热应激会导致记忆增强（即持续 24 小时的 LTM）。然而，在温水中国，呼吸频率也会增加，这可能解释了增强的记忆。因此，我们在训练前 4 小时或训练后 1 小时施加热应激（30°C 1 小时）。这并没有改变蜗牛在经历训练期间的基础呼吸率。然而，无论是在单次 TS 之前还是之后经历热应激，都会导致记忆增强，这种增强的记忆可持续长达 48 小时（即 LTM）。我们的结论是，记忆增强是由于与热刺激相关的应激引起的。
