Neuochemical and USV measurements of the effects of morphine withdrawal in rats

Data was acquired to investigate the effects of morphine withdrawal in rats, both in the brain neurochemistry and ultrasonic vocalisation. To this end, a following experiment was performed. 38 adult male Sprague–Dawley rats were used in the experiment, divided into four groups: Saline-Control (10), Morphine-Control (9), Saline-Withdrawal (10) and Morphine-Withdrawal (9). Morphine in dose 10.0 mg/kg (s.c.) was administered repeatedly to the morphine groups over a 14 day period; saline solution was administered repeatedly (1.0 ml/kg) to other groups in the same manner. Administration was performed in testing cages in a group of four animals. The testing room was situated in a remote part of the laboratory, and significantly different than home cage room, both in the lighting conditions and in the arrangement of spatial cues, which were constant throughout the whole experiment. All animals were kept for 30 min in the testing box after each saline or morphine injection. On day 14, Morph-Control group and control Saline-Control group were exposed to the context of drug administration, and the ultrasonic vocalizations were recorded for 20 min. Withdrawal groups, 30 min after last injection, were left undisturbed (in their home cages), whilst they were subjected to 2-week withdrawal period. On day 28, the rats were re-exposed to the context of morphine/saline administration and ultrasonic vocalization was recorded. Each rat was immediately decapitated after USVs recording session, and its brain tissues were frozen. The USVs were recorded individually for each rat, in a dark room with dim red light. USV recordings were processed using a proprietary RatRec Pro software; individual calls were extracted and counted. All identified episodes were of the "50 kHz appetitive" class, no "aversive 22 kHz" alarm calls were recorded. For each rat, tissue samples of 6 brain structures were extracted: medial prefrontal cortex (mPFC), nucleus accumbens (NAcc), striatum (Cpu), hippocampus (Hipp), amygdala and ventral tegmental area (VTA). In each sample, levels of 15 compounds were measured: norepinephrine (NA), 3-methoxy-4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), dopamine (DA), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), serotonin (5-HT), 3-methoxytyramine (3-MT), taurine, glutamine (Gln), glycine (Gly), aspartic acid (Asp), glutamic acid (Glu), alanine (Ala) and gamma-aminobutyric acid (GABA).

本数据集旨在探究吗啡戒断对大鼠脑神经化学与超声发声的影响，为此开展了如下实验。本次实验共使用38只成年雄性斯普拉格-道利（Sprague–Dawley）大鼠，分为4组：生理盐水对照组（Saline-Control，10只）、吗啡对照组（Morphine-Control，9只）、生理盐水戒断组（Saline-Withdrawal，10只）及吗啡戒断组（Morphine-Withdrawal，9只）。吗啡组以10.0 mg/kg的剂量经皮下注射（s.c.）连续给药14天；其余各组以相同方式连续给予生理盐水（剂量为1.0 ml/kg）。给药操作在每笼4只动物的测试笼中进行。测试室位于实验室偏远区域，与饲养笼所在房间的光照条件及空间线索布局均存在显著差异，且整个实验期间环境参数保持恒定。每次注射生理盐水或吗啡后，所有动物均需在测试箱中停留30分钟。第14天时，吗啡对照组与生理盐水对照组大鼠被暴露于给药环境，同时录制20分钟的超声发声（ultrasonic vocalisation, USV）。戒断组在末次给药30分钟后置于饲养笼中不予打扰，随后经历为期2周的戒断阶段。第28天时，大鼠再次被暴露于吗啡/生理盐水给药环境，并录制超声发声。完成USV录制后，立即对每只大鼠实施断头处理，采集其脑组织并冷冻保存。USV录制为单只大鼠单独进行，录制环境为配备昏暗红光的暗室。USV数据采用专属RatRec Pro软件进行处理，提取并计数单个发声事件。所有识别出的发声均属于"50 kHz 趋近性"类别，未记录到"厌恶性22 kHz"警报叫声。针对每只大鼠，采集6个脑结构的组织样本：内侧前额叶皮层（medial prefrontal cortex, mPFC）、伏隔核（nucleus accumbens, NAcc）、纹状体（striatum, Cpu）、海马体（hippocampus, Hipp）、杏仁核及腹侧被盖区（ventral tegmental area, VTA）。对每个组织样本，检测15种化合物的含量：去甲肾上腺素（norepinephrine, NA）、3-甲氧基-4-羟基苯乙二醇（3-methoxy-4-hydroxyphenylglycol, MHPG）、3,4-二羟基苯乙酸（3,4-dihydroxyphenylacetic acid, DOPAC）、多巴胺（dopamine, DA）、5-羟基吲哚乙酸（5-hydroxyindoleacetic acid, 5-HIAA）、高香草酸（homovanillic acid, HVA）、血清素（serotonin, 5-HT）、3-甲氧基酪胺（3-methoxytyramine, 3-MT）、牛磺酸、谷氨酰胺（glutamine, Gln）、甘氨酸（glycine, Gly）、天冬氨酸（aspartic acid, Asp）、谷氨酸（glutamic acid, Glu）、丙氨酸（alanine, Ala）及γ-氨基丁酸（gamma-aminobutyric acid, GABA）。