title: Heat shock affects cell cycling in the neural plate of cultured rat embryos: a flow cytometric study.
abstract: The effects of heat shock on cell cycling in the mammalian neuroectoderm were determined by applying heat shocks to cultured rat embryos at the neural plate stage, as part of a study on the teratogenic effects of heat shock on neural development. The heat shocks had been characterized previously (Walsh et al.: Teratology 36:181-191, 1987) with respect to their effects on the gross morphological development of the rat embryos. The effects on cell cycling were observed in DNA histograms of neural plate cells recorded in a flow cytometer after staining with DAPI. The mild heat shock (42 degrees C for 10 min) arrested cells at entry to S phase. The teratogenic heat shock (43 degrees C for 7.5 min) arrested cells at entry to S phase also but for a longer time and inhibited cycling through S phase. After each arrest, a synchronized peak of cells later entered S phase and progressed through the cycle. The induced-thermotolerance heat shock, which was the mild heat shock followed after an interval by the teratogenic heat shock, showed that pre-treatment with the mild heat shock reduced the magnitude of the response to the teratogenic heat shock. The cell-cycle inhibitor ICRF 159 showed the effects on cycling rates of the heat-shock treatments. The arrest of cells at entry to S phase by heat shock may function to prevent cells entering DNA synthesis under non-optimal conditions. We report estimates of proportions of non-proliferative cells in the neural plate of the rat embryos.
authors.affiliation: Veterinary Clinical Sciences, University of Sydney, NSW, Australia.
authors.forename: D A
authors.initials: DA
authors.lastname: Walsh
authors.forename: V B
authors.initials: VB
authors.lastname: Morris
mesh_terms: D000818:Animals; D002453:Cell Cycle; D005434:Flow Cytometry; D006358:Hot Temperature; D007399:Interphase; D009420:Nervous System / Q000196:embryology*; D009924:Organ Culture Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D011929:Razoxane / Q000494:pharmacology
chemical_list: D011929:Razoxane