title: 2'-Deoxyadenosine causes cell death in embryonic chicken sympathetic ganglia and brain.
abstract: Previous work has shown that nucleosides produce apoptosis in sympathetic ganglion (SG) cells in vitro. The present study examined the effects of nucleosides on the development of the chick embryo in vivo with special attention to the SG and the optic tectum of the central nervous system. In the presence of an adenosine deaminase inhibitor, adenosine and 2'-deoxyadenosine (2'-dAdo) produced different toxicity patterns: both adenosine and 2'-dAdo were toxic to E3 embryos, but only 2'-dAdo was toxic at later stages (E6 1/2, E11). Dosage experiments on E6 1/2 embryos showed that adenosine was less toxic than 2'-dAdo and that 2'-dAdo in sublethal doses was teratogenic. We also examined the effects of 2'-dAdo on embryonic chicken SG and optic tectum in vivo to determine whether sublethal doses of 2'-dAdo produced cell death in these centers on E6 1/2 and 10. In the E6 1/2 SG, 2'-dAdo produced significant neuron loss (83%) and a decrease in SG volume (65%); however, at E10, there was only minor cell loss (7%) and no significant change in SG volume. In the optic tectum at E6 1/2, cell loss was confined mainly to the tectal ventricular zone, but there was little sign of cell loss in this organ at E10. Since cell production is vigorous in the SG and optic tectum at E6 1/2 but relatively low at E10, 2'-dAdo appears to work by stopping cell proliferation. The ineffectiveness of 2'-dAdo at E10 may result from the lethality of 2'-dAdo to the embryo at low concentrations (30 microM) in vivo, well below the apoptosis-inducing concentrations employed in vitro (100-300 microM). These data extend previous findings showing that purine and pyrimidine metabolism plays an important role in development.
authors.affiliation: Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48202, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhao
authors.forename: W J
authors.initials: WJ
authors.lastname: Crossland
authors.forename: J S
authors.initials: JS
authors.lastname: Kulkarni
authors.forename: T D
authors.initials: TD
authors.lastname: Wakade
authors.forename: A R
authors.initials: AR
authors.lastname: Wakade
mesh_terms: D000818:Animals; D019521:Body Patterning; D001921:Brain / Q000187:drug effects / Q000196:embryology* / Q000473:pathology; D016923:Cell Death; D002642:Chick Embryo; D003839:Deoxyadenosines / Q000633:toxicity*; D005728:Ganglia, Sympathetic / Q000187:drug effects / Q000196:embryology* / Q000473:pathology; D009153:Mutagens / Q000633:toxicity; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000473:pathology; D013477:Superior Colliculi / Q000187:drug effects / Q000196:embryology / Q000473:pathology
chemical_list: D003839:Deoxyadenosines; D009153:Mutagens; C058118:2'-deoxyadenosine