title: Early chick neuroretinal responses following direct exposure to methotrexate.
abstract: Explants of 4.5-day-old chick embryonic neuroretinas with mesenchyme were exposed to Methotrexate (MTX) in medium 199 with embryo extract. Proliferative responses of the cultured neuroretinas were followed radioautographically by administration of 3H-thymidine to the cultures. The DNA synthetic, mitotic and pyknotic responses of the ventricular cells of the neuroretina were followed over a 16-hour period. The responses observed suggested that MTX caused a synchronization of the ventricular cells in the pre-mitotic phases with no direct inhibition of mitosis. Furthermore, prolonged exposure to MTX resulted in the accumulation of labeled pyknotic cells, indicating a decline in the regenerative capacity of the proliferative ventricular cells.
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002642:Chick Embryo; D004247:DNA / Q000096:biosynthesis; D004848:Epithelium / Q000187:drug effects; D008727:Methotrexate / Q000009:adverse effects*; D008938:Mitosis / Q000187:drug effects; D008954:Models, Biological; D009900:Optic Nerve / Q000187:drug effects*; D012160:Retina / Q000187:drug effects*
chemical_list: D004247:DNA; D008727:Methotrexate