title: Overdose of D-serine Induces Movement Disorder and Neuromuscular Changes of Zebrafish Larvae.
abstract: D-serine is a well-known activator of N-methyl-D-aspartate receptors; however, little is known about the teratogenic effects of D-serine overdose during early embryonic development. Here, we used zebrafish as a model to test toxicity and teratogenicity, since they have transparent eggs, making the organogenesis of zebrafish embryos easier to be observed. After D-serine injection (100-1000 ppm), the most evident defective phenotypes were bent trunk phenotypes, including malformed somite boundary, twisted body axis and shorter body length. As the injection dosages increased, the rates of embryos with bent trunk phenotypes decreased (0% for 0 ppm, n=573; 59.9~84.3% for 100-1000 ppm of D-serine, n=383-451). In addition, D-serine-injected embryos exhibited significantly reduced the frequencies of spontaneous in-chorion contraction (21.7 for 0 ppm vs. 18.3-0.9 for 100-1000 ppm D-serine, n=30) in comparison with mock-treated controls (0 ppm). Subtle changes are easily observed by staining with specific monoclonal antibodies F59, Znp1, Zn5 and α-bungarotoxin to detect morphological changes in muscle fibers, primary motor axons, secondary motor axon projections and neuromuscular junctions, respectively. Our data show that overdose of D-serine leads to misalignment of muscle fibers and motor neuron defects, especially secondary motor neuron axonal growth defects.
authors.affiliation: Department of Chemistry, Tamkang University, No. 151 Ying-chuan Road, Tamsui, New Taipei City 251, Taiwan.
authors.forename: Xing-Guang
authors.initials: XG
authors.lastname: Chen
authors.affiliation: Division of Basic Research, Koo Foundation Sun Yat-Sen Cancer Center, No. 125, Lide Road, Beitou, Taipei, Taiwan.
authors.forename: Yun-Hsin
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Department of Mathematics, Tamkang University, No. 151, Ying-chuan Road, Tamsui, New Taipei City, Taiwan.
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Wen
authors.affiliation: Department of Chemistry, Tamkang University, No. 151 Ying-chuan Road, Tamsui, New Taipei City 251, Taiwan.
authors.forename: Yau-Hung
authors.initials: YH
authors.lastname: Chen
keywords: D-serine; NMDA receptor; developmental toxicity