近日,来自国外的研究者揭示了大脑血清素(也称为快乐荷尔蒙)的水平,这种快乐荷尔蒙(happy hormone)在个体早年的时候受肠道内大量的细菌所调节,这项研究刊登在了国际著名杂志Molecular Psychiatry上。这项研究揭示了正常成年人大脑功能的发育依赖于其肠道内的微生物。血清素主要调节情绪和情感,其水平可以随着压力、焦虑以及大多临床的抗抑郁药物所改变。
UCC的研究者使用无菌小鼠模型来研究其在早年的时候机体细菌的存在,是否可以影响小鼠成年后的大脑血清素水平。这项研究同时也揭示了这种影响是受性别依赖的,相比雌性动物来说,雄性动物更易受影响。早期研究中研究者揭示了微生物组-肠道-大脑轴的存在对于维持机体健康以及影响大脑和行为至关重要。
研究者John F Cryan表示,作为神经科学家,这些发现非常有意思,肠道的细菌对于维持大脑和肠道之间的定向交流至关重要。而且这也为我们治疗脑部障碍提供了基于微生物的一些治疗措施。
这项研究蕴含多种健康效应,包括微生物的操作对于大脑功能具有深远的影响。研究者对于其发现非常兴奋,他们发现了微生物群落对于一般的健康必不可少,同时研究者也揭示了微生物对于我们的精神心理健康也是很重要的。(生物谷Bioon.com)
编译自:Early Gut Bacteria Regulate Happiness
编译者:T.Shen
doi:10.1038/mp.2012.77
PMC:
PMID:
The microbiome-gut-brain axis during early life regulates the hippocampal serotonergic system in a sex-dependent manner
G Clarke, S Grenham, P Scully, P Fitzgerald, R D Moloney, F Shanahan, T G Dinan and J F Cryan
Bacterial colonisation of the intestine has a major role in the post-natal development and maturation of the immune and endocrine systems. These processes are key factors underpinning central nervous system (CNS) signalling. Regulation of the microbiome–gut–brain axis is essential for maintaining homeostasis, including that of the CNS. However, there is a paucity of data pertaining to the influence of microbiome on the serotonergic system. Germ-free (GF) animals represent an effective preclinical tool to investigate such phenomena. Here we show that male GF animals have a significant elevation in the hippocampal concentration of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid, its main metabolite, compared with conventionally colonised control animals. Moreover, this alteration is sex specific in contrast with the immunological and neuroendocrine effects which are evident in both sexes. Concentrations of tryptophan, the precursor of serotonin, are increased in the plasma of male GF animals, suggesting a humoral route through which the microbiota can influence CNS serotonergic neurotransmission. Interestingly, colonisation of the GF animals post weaning is insufficient to reverse the CNS neurochemical consequences in adulthood of an absent microbiota in early life despite the peripheral availability of tryptophan being restored to baseline values. In addition, reduced anxiety in GF animals is also normalised following restoration of the intestinal microbiota. These results demonstrate that CNS neurotransmission can be profoundly disturbed by the absence of a normal gut microbiota and that this aberrant neurochemical, but not behavioural, profile is resistant to restoration of a normal gut flora in later life.