Escobedo-Avila Itzel, Vargas-Romero Fernanda, Molina-Hernández Anayansi, López-González Rodrigo, Cortés Daniel, De Carlos Juan A, Velasco Iván
Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México D,F,-04510, Mexico.
Mol Brain. 2014 Aug 12;7:58. doi: 10.1186/s13041-014-0058-x.
Histamine (HA) regulates the sleep-wake cycle, synaptic plasticity and memory in adult mammals. Dopaminergic specification in the embryonic ventral midbrain (VM) coincides with increased HA brain levels. To study the effect of HA receptor stimulation on dopamine neuron generation, we administered HA to dopamine progenitors, both in vitro and in vivo.
Cultured embryonic day 12 (E12) VM neural stem/progenitor cells expressed transcripts for HA receptors H1R, H2R and H3R. These undifferentiated progenitors increased intracellular calcium upon HA addition. In HA-treated cultures, dopamine neurons significantly decreased after activation of H1R. We performed intrauterine injections in the developing VM to investigate HA effects in vivo. HA administration to E12 rat embryos notably reduced VM Tyrosine Hydroxylase (TH) staining 2 days later, without affecting GABA neurons in the midbrain, or serotonin neurons in the mid-hindbrain boundary. qRT-PCR and Western blot analyses confirmed that several markers important for the generation and maintenance of dopaminergic lineage such as TH, Lmx1a and Lmx1b were significantly diminished. To identify the cell type susceptible to HA action, we injected embryos of different developmental stages, and found that neural progenitors (E10 and E12) were responsive, whereas differentiated dopaminergic neurons (E14 and E16) were not susceptible to HA actions. Proliferation was significantly diminished, whereas neuronal death was not increased in the VM after HA administration. We injected H1R or H2R antagonists to identify the receptor responsible for the detrimental effect of HA on dopaminergic lineage and found that activation of H1R was required.
These results reveal a novel action of HA affecting dopaminergic lineage during VM development.
组胺（HA）调节成年哺乳动物的睡眠 - 觉醒周期、突触可塑性和记忆。胚胎腹侧中脑（VM）中的多巴胺能特化与脑内HA水平升高同时发生。为了研究HA受体刺激对多巴胺神经元生成的影响，我们在体外和体内对多巴胺祖细胞施用了HA。
培养的胚胎第12天（E12）VM神经干细胞/祖细胞表达HA受体H1R、H2R和H3R的转录本。这些未分化的祖细胞在添加HA后细胞内钙增加。在HA处理的培养物中，激活H1R后多巴胺神经元显著减少。我们在发育中的VM中进行子宫内注射以研究HA在体内的作用。对E12大鼠胚胎施用HA后，2天后VM酪氨酸羟化酶（TH）染色明显减少，而不影响中脑的GABA神经元或中后脑边界的5-羟色胺神经元。qRT-PCR和蛋白质印迹分析证实，对多巴胺能谱系的产生和维持重要的几种标志物，如TH、Lmx1a和Lmx1b显著减少。为了确定对HA作用敏感的细胞类型，我们注射了不同发育阶段的胚胎，发现神经祖细胞（E10和E12）有反应，而分化的多巴胺能神经元（E14和E16）对HA作用不敏感。HA给药后VM中的增殖显著减少，而神经元死亡没有增加。我们注射H1R或H2R拮抗剂以确定对多巴胺能谱系产生有害作用的HA所涉及的受体，发现需要激活H1R。
这些结果揭示了HA在VM发育过程中影响多巴胺能谱系的新作用。
