表达各种不同神经传输物质的神经元之间的平衡，被认为是在脑发育过程中由基因控制确定的。这是一个关键的步骤，它使得各组神经元之间能够传递信号。现在，由Davide Dulcis 和 Nicholas Spitzer完成的一项新的研究表明，生理刺激也能调控一组神经元中所表达的神经传输物质类别。
研究发现，暴露于自然光的蝌蚪会增加表达多巴胺的中枢神经元的数量，而这反过来又会影响皮肤颜色变化及它们的伪装潜力。本期封面所示为在自然环境中适应了黑暗的一只蝌蚪和适应了光照的一只蝌蚪，其中一只比另一只伪装更好。这一发现也许还有更广泛的意义，并且还可能与由生源胺调控的认知状态的变化有关。有趣的是，人们用亮光疗法治疗季节性情感障碍患者已有20多年了。季节性情感障碍是一种抑郁症，被发现与多巴胺信号作用障碍有关。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 456, 195-201 (13 November 2008) | doi:10.1038/nature07569
Illumination controls differentiation of dopamine neurons regulating behaviour
Davide Dulcis1 & Nicholas C. Spitzer
Neurobiology Section, Division of Biological Sciences and Center for Molecular Genetics, Kavli Institute for Brain and Mind, UCSD La Jolla, California 92093-0357, USA
Abstract
Specification of the appropriate neurotransmitter is a crucial step in neuronal differentiation because it enables signalling among populations of neurons. Experimental manipulations demonstrate that both autonomous and activity-dependent genetic programs contribute to this process during development, but whether natural environmental stimuli specify transmitter expression in a neuronal population is unknown. We investigated neurons of the ventral suprachiasmatic nucleus that regulate neuroendocrine pituitary function in response to light in teleosts, amphibia and primates. Here we show that altering light exposure, which changes the sensory input to the circuit controlling adaptation of skin pigmentation to background, changes the number of neurons expressing dopamine in larvae of the amphibian Xenopus laevis in a circuit-specific and activity-dependent manner. Neurons newly expressing dopamine then regulate changes in camouflage colouration in response to illumination. Thus, physiological activity alters the numbers of behaviourally relevant amine-transmitter-expressing neurons in the brain at postembryonic stages of development. The results may be pertinent to changes in cognitive states that are regulated by biogenic amines.
