Testing Drosophila Olfaction with a Y-maze Assay

Detecting signals from the environment is essential for animals to ensure their survival. To this aim, they use environmental cues such as vision, mechanoreception, hearing, and chemoperception through taste, via direct contact or through olfaction, which represents the response to a volatile molecule acting at longer range. Volatile chemical molecules are very important signals for most animals in the detection of danger, a source of food, or to communicate between individuals. Drosophila melanogaster is one of the most common biological models for scientists to explore the cellular and molecular basis of olfaction. In order to highlight olfactory abilities of this small insect, we describe a modified choice protocol based on the Y-maze test classically used with mice. Data obtained with Y-mazes give valuable information to better understand how animals deal with their perpetually changing environment. We introduce a step-by-step protocol to study the impact of odorants on fly exploratory response using this Y-maze assay.     

慢性复合应激增强大鼠空间学习和记忆能力

本文观察了慢性复合应激对大鼠学习与记忆功能的影响。实验采用成年 Wistar 大鼠, 将其随机分成应激组和对照组。采用垂直旋转、睡眠剥夺、噪音刺激和夜间光照4 种应激原, 无规律地交替刺激动物 6 周, 每天6 h, 制作慢性复合应激动物模型。采用 Morris 水迷宫和 Y- 迷宫测试大鼠学习与记忆成绩,并用 Cresyl violet 染色法对大鼠海马结构进行神经细胞计数。结果显示,应激组动物慢性复合应激后, 在 Morris 水迷宫内寻找隐蔽平台所需的时间(潜伏期)比对照组的明显地短(P<0.05), 表明应激鼠的空间记忆能力明显强于对照鼠;在 Y- 迷宫内寻找安全区的正确率比对照组的明显地高(P<0.05), 表明应激鼠的明暗分辨学习能力明显强于对照鼠; 应激鼠慢性复合应激后, 其海马结构齿状回、CA3 和CA1 区神经细胞密度极明显地高于对照鼠(P<0.001)。这些结果提示, 慢性复合应激可增强大鼠空间记忆能力和明暗分辨学习能力。本文并对慢性复合应激模式增强大鼠学习和记忆能力的可能原因进行了讨论。     

Learning ability of triploid brook trout

Triploid brook trout ( Salvelinus fontinalis ) did not differ from diploids in their initial directional preference within a Y-maze, electrical shock response threshold, or learning ability.     

大鼠眶额叶皮质受损破坏新异性探索行为

利用旷场测试和Y-迷宫测试两种行为模型检测了双侧眶额叶（orbitofrontal cortex, OFC）电损伤或假损伤雄性SD大鼠的新异性探索行为, 探讨了OFC在大鼠探索新异环境中的作用。旷场测试的结果发现,OFC损伤大鼠的行走距离和直立次数较假损组有明显降低;同时,在Y-迷宫测试中与假损伤组大鼠相比,OFC损伤大鼠在新异臂的访问时间和穿梭次数明显降低。提示眶额叶皮质在大鼠新异性探索行为中起着重要作用。     

Nodakenin, a coumarin compound, ameliorates scopolamine-induced memory disruption in mice

Nodakenin is a coumarin compound initially isolated from the roots of Angelica gigas. In the present study, we investigated the effects of nodakenin on learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) using the passive avoidance test, the Y-maze test, and the Morris water maze test in mice. Nodakenin (10 mg/kg, p.o.) administration significantly reversed scopolamine-induced cognitive impairments in the passive avoidance test and the Y-maze test (P<0.05), and also reduced escape latency during training in the Morris water maze test (P<0.05). Moreover, swimming times and distances within the target zone of the Morris water maze were greater in the nodakenin-treated group than in the scopolamine-treated group (P<0.05). In an in vitro study, nodakenin was found to inhibit acetylcholinesterase activity in a dose-dependent manner (IC(50)=84.7 microM). In addition, nodakenin was also found to inhibit acetylcholinesterase activity for 6 h in an ex-vivo study. These results suggest that nodakenin may be a useful for the treatment of cognitive impairment, and that its beneficial effects are mediated, in part, via the enhancement of cholinergic signaling.     

Performance of mice in discrimination of liquor odors: behavioral evidence for olfactory attention

We examined performance of mice in discrimination of liquor odors by Y-maze behavioral assays. Thirsty mice were initially trained to choose the odor of a red wine in the Y-maze. After successful training (>70% concordance for each trained mouse), the individual mice were able to discriminate the learned red wine from other liquors, including white wine, rosé wine, sake, and plum liqueur. However, when the mice were tested to distinguish fine differences between 2 brands of red wine, their performance significantly varied among the individual trained mice. Among 10 mice tested, 2 mice were able to discriminate between the red wines (>75% concordance) whereas 6 mice failed to distinguish between them (50-67% concordance, where chance could be assumed to be 50%). More importantly, 2 other mice exhibited lower than 30% concordance, indicating that they were more attracted to the nonrewarded red wine compared with the learned one. This result suggested that the individual mice directed attention to different subsets of volatile components emanating from the rewarded red wine, when they were trained to choose the liquor odor in the Y-maze. Selective attention of mice was also observed in Y-maze behavioral assays using the mixtures of 3 or less pure odorants. Additionally, we also observed that the olfactory attention of mice could be modified through their learning experiences.     

Investigations on training, recall and reversal learning of a Y-maze by dwarf goats (Capra hircus): the impact of lateralisation

We investigated maze learning in dwarf goats (Capra hircus) and the impact of lateralisation on learning. Lateralisation refers to the collection of phenomena in which external stimuli are perceived and processed differentially on the two sides of the brain and/or certain behaviours are preferentially performed by one side of the body. We trained 29 dwarf goats in a Y-maze, directing them to the opposite alley from that chosen in a free pre-run. In total, 13 goats were trained to the left alley (L-goats) and 16 goats to the right alley (R-goats). Recall of the trained alley was tested three months later. We then analysed reversal learning across 10 reversals. During training, the direction of the alley had an impact on learning. The number of runs required to reach the learning criterion was significantly lower in the L- than the R-goats. The goats recalled the trained alley three months later, with no difference between the L- and the R-goats. During the reversal learning, the reversal only tended to impact learning performance, whereas the directions of the new and the initially trained alley did not. Goats did not adopt a general rule with which to master the maze (e.g., win-stay/lose-shift) across the 10 reversals. Our results indicate a right hemisphere bias in the processing of visuospatial cues in the maze during initial training; however, no such impact was detected during reversal learning.     

Neophobia, sensory and cognitive functions, and hedonic responses in vitamin D receptor mutant mice

Vitamin D is a seco-steroid hormone with multiple actions in the brain, mediated through the nuclear vitamin D receptor (VDR). We have recently shown that mutant mice lacking functional VDR demonstrate altered emotional behavior and specific motor deficits. Here we further examine phenotype of these mice, testing their novelty responses, as well as cognitive and sensory (olfactory and gustatory) functions in the novel food, two-trial Y-maze and tastant consumption tests. In addition, we study depression-like behavior in these mice, using anhedonia-based sucrose preference test. Overall, VDR mutant mice showed neophobic response in several different tests, but displayed unimpaired olfactory and gustatory functions, spatial memory and baseline hedonic responses. Collectively, these data confirm that mutation of VDR in mice leads to altering emotional/anxiety states, but does not play a major role in depression, as well as in the regulation of some sensory and cognitive processes. These results support the role of the vitamin D/VDR neuroendocrine system in the regulation of behavior, and may have clinical relevance, enabling a better focus on psychiatric and behavioral disorders associated with dysfunctions in this neuroendocrine system.     

Synthesis,SAR study,and biological evaluation of novel 2,3-dihydro-1H-imidazo[1,2-a]benzimidazole derivatives as phosphodiesterase 10A inhibitors

Phosphodiesterase 10A (PDE10A) inhibitors were designed and synthesized based on the dihydro-imidazobenzimidazole scaffold. Compound 5a showed moderate inhibitory activity and good permeability, but unfavorable high P-glycoprotein (P-gp) liability for brain penetration. We performed an optimization study to improve both the P-gp efflux ratio and PDE10A inhibitory activity. As a result, 6d was identified with improved P-gp liability and high PDE10A inhibitory activity. Compound 6d also showed satisfactory brain penetration, suppressed phencyclidine-induced hyperlocomotion and improved MK-801-induced working memory deficit.     

吗啡和胆碱能拮抗剂联合给药对小鼠Y迷宫空间记忆提取及活动性的影响(英文）

吗啡和胆碱能系统的相互作用已在多项研究中提到,本实验想查明吗啡是否能和胆碱能拮抗剂、东莨菪碱以及阿托品共同作用对小鼠的Y迷宫空间识别记忆提取产生影响。采用测试前腹腔给药的方法,选用3种剂量的吗啡(5、1.5、0.5mg/kg),两种剂量的东莨菪碱(1、0.1mg/kg),以及两种剂量的阿托品(0.5、0.1mg/kg),剂量由高到低相配对作为联合给药的手段。其结果表明:1)0.5mg/kg低剂量吗啡与0.1mg/kg低剂量的东莨菪碱,或与0.1mg/kg低剂量的阿托品联合给药的小鼠,在记忆提取测试中,空间探查行为(各臂停留时间百分比)对新异臂没有偏好,而新奇探索行为(各臂访问次数百分比)仍保持了对新异臂的偏好,而相应剂量药物单独给药的小鼠记忆提取均没有被损害;2)吗啡能和东莨菪碱相互作用使小鼠的活动性显著增强。暗示吗啡和胆碱能拮抗剂对小鼠空间记忆提取的破坏存在一定程度的相互作用。