Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, New York, USA.
Addict Biol. 2022 Nov;27(6):e13238. doi: 10.1111/adb.13238.
Embryonic exposure to ethanol increases the risk for alcohol use disorder in humans and stimulates alcohol-related behaviours in different animal models. Evidence in rats and zebrafish suggests that this phenomenon induced by ethanol at low-moderate concentrations involves a stimulatory effect on neurogenesis and density of hypothalamic neurons expressing the peptides, hypocretin/orexin (Hcrt) and melanin-concentrating hormone (MCH), known to promote alcohol consumption. Building on our report in zebrafish showing that ethanol induces ectopic expression of Hcrt neurons outside the hypothalamus, we investigated here whether embryonic ethanol exposure also induces ectopic peptide neurons in rats similar to zebrafish and affects their morphological characteristics and if these ectopic neurons are functional and have a role in the ethanol-induced disturbances in behaviour. We demonstrate in rats that ethanol at a low-moderate dose, in addition to increasing Hcrt and MCH neurons in the lateral hypothalamus where they are normally concentrated, induces ectopic expression of these peptide neurons further anterior in the nucleus accumbens core and ventromedial caudate putamen where they have not been previously observed and causes morphological changes relative to normally located hypothalamic neurons. Similar to rats, embryonic ethanol exposure at a low-moderate dose in zebrafish induces ectopic Hcrt neurons anterior to the hypothalamus and alters their morphology. Notably, laser ablation of these ectopic Hcrt neurons blocks the behavioural effects induced by ethanol exposure, including increased anxiety and locomotor activity. These findings suggest that the ectopic peptide neurons are functional and contribute to the ethanol-induced behavioural disturbances related to the overconsumption of alcohol.
胚胎暴露于乙醇会增加人类患酒精使用障碍的风险,并刺激不同动物模型中的酒精相关行为。大鼠和斑马鱼的证据表明,这种由低浓度乙醇诱导的现象涉及对神经发生和表达肽的下丘脑神经元密度的刺激,这些肽已知可促进酒精消费,包括食欲肽/orexin(Hcrt)和黑色素浓缩激素(MCH)。基于我们在斑马鱼中报告的乙醇诱导下丘脑外异位表达 Hcrt 神经元的发现,我们在此研究了胚胎乙醇暴露是否也会在大鼠中诱导类似的异位肽神经元,并影响它们的形态特征,以及这些异位神经元是否具有功能并在乙醇诱导的行为障碍中发挥作用。我们在大鼠中证明,低剂量乙醇除了增加外侧下丘脑中正常集中的 Hcrt 和 MCH 神经元外,还诱导这些肽神经元在以前未观察到的伏隔核核心和腹侧尾状苍白球中异位表达,并导致与正常位于下丘脑神经元相比的形态变化。与大鼠相似,斑马鱼中低剂量胚胎乙醇暴露会诱导下丘脑前部异位 Hcrt 神经元,并改变其形态。值得注意的是,这些异位 Hcrt 神经元的激光消融可阻止乙醇暴露引起的行为效应,包括焦虑和运动活性增加。这些发现表明,异位肽神经元具有功能,并有助于与过度饮酒相关的乙醇诱导的行为障碍。