Neuroscience Institute, CNR, Milan, Italy`.
Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy.
Prog Neuropsychopharmacol Biol Psychiatry. 2021 Dec 20;111:110334. doi: 10.1016/j.pnpbp.2021.110334. Epub 2021 Apr 24.
Nicotine withdrawal syndrome is a major clinical problem. Animal models with sufficient predictive validity to support translation of pre-clinical findings to clinical research are lacking.
We evaluated the behavioural and neurochemical alterations in zebrafish induced by short- and long-term nicotine withdrawal.
Zebrafish were exposed to 1 mg/L nicotine for 2 weeks. Dependence was determined using behavioural analysis following mecamylamine-induced withdrawal, and brain nicotinic receptor binding studies. Separate groups of nicotine-exposed and control fish were assessed for anxiety-like behaviours, anhedonia and memory deficits following 2-60 days spontaneous withdrawal. Gene expression analysis using whole brain samples from nicotine-treated and control fish was performed at 7 and 60 days after the last drug exposure. Tyrosine hydroxylase (TH) immunoreactivity in pretectum was also analysed.
Mecamylamine-precipitated withdrawal nicotine-exposed fish showed increased anxiety-like behaviour as evidenced by increased freezing and decreased exploration. H-Epibatidine labeled heteromeric nicotinic acethylcholine receptors (nAChR) significantly increased after 2 weeks of nicotine exposure while I-αBungarotoxin labeled homomeric nAChR remained unchanged. Spontaneous nicotine withdrawal elicited anxiety-like behaviour (increased bottom dwelling), reduced motivation in terms of no preference for the enriched side in a place preference test starting from Day 7 after withdrawal and a progressive decrease of memory attention (lowering discrimination index). Behavioural differences were associated with brain gene expression changes: nicotine withdrawn animals showed decreased expression of chrna 4 and chrna7 after 60 days, and of htr2a from 7 to 60 days.The expression of c-Fos was significantly increased at 7 days. Finally, Tyrosine hydroxylase (TH) immunoreactivity increased in dorsal parvocellular pretectal nucleus, but not in periventricular nucleus of posterior tuberculum nor in optic tectum, at 60 days after withdrawal.
Our findings show that nicotine withdrawal induced anxiety-like behaviour, cognitive alterations, gene expression changes and increase in pretectal TH expression, similar to those observed in humans and rodent models.
尼古丁戒断综合征是一个主要的临床问题。目前缺乏具有足够预测效度的动物模型，无法将临床前研究结果转化为临床研究。
我们评估了短期和长期尼古丁戒断对斑马鱼行为和神经化学的影响。
斑马鱼暴露于 1mg/L 尼古丁中 2 周。使用美加仑胺诱导戒断后的行为分析和脑烟碱型乙酰胆碱受体结合研究来确定依赖性。在自发戒断 2-60 天后，分别评估尼古丁暴露组和对照组的焦虑样行为、快感缺失和记忆缺陷。在最后一次药物暴露后 7 天和 60 天，使用来自尼古丁处理组和对照组的全脑样本进行基因表达分析。还分析了前脑桥上的酪氨酸羟化酶（TH）免疫反应性。
美加仑胺诱发戒断的尼古丁暴露鱼表现出增加的焦虑样行为，表现为增加的冻结和减少的探索。2 周尼古丁暴露后，H-Epibatidine 标记的异源烟碱型乙酰胆碱受体（nAChR）显著增加，而 I-αBungarotoxin 标记的同源 nAChR 保持不变。自发尼古丁戒断引起焦虑样行为（增加底部栖息），从戒断后第 7 天开始的位置偏好测试中，动机减少（对丰富侧没有偏好），记忆注意力逐渐下降（降低辨别指数）。行为差异与大脑基因表达变化相关：尼古丁戒断动物在 60 天后显示 chrna4 和 chrna7 表达减少，7 天至 60 天后 htr2a 表达减少。7 天时 c-Fos 的表达显著增加。最后，在戒断后 60 天时，背侧小细胞前脑桥核中的酪氨酸羟化酶（TH）免疫反应性增加，但在视顶盖后的室周核和视束中没有增加。
我们的发现表明，尼古丁戒断引起焦虑样行为、认知改变、基因表达变化和前脑桥 TH 表达增加，与人类和啮齿动物模型观察到的相似。
