Cold stress related alteration of RNA biosynthesis in brain cortex of mother-deprived newborn rats

• Published in: Life sciences (1973) 1997-05, Vol.60 (24), p.2165-2171
• Main Authors: Ibarra, Gustavo R., Paratcha, Gustavo Ch, Rodriguez, Jorge A., Napp, Mónica I., Azcurra, Julio M.
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn - genetics; Animals, Newborn - metabolism; Body Temperature Regulation; brain cortex; brain development; Cerebral Cortex - metabolism; cold stress; Cold Temperature - adverse effects; Kinetics; Maternal Deprivation; Rats; Rats, Wistar; RNA - biosynthesis; Stress, Physiological - metabolism
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/S0024-3205(97)00231-2

We studied the influence of maternal deprivation on the RNA biosynthesis in the brain cortex of 10 day-old rats. Mother-deprived pups, placed at 25 °C showed a reduction in body temperature of 6 +/− 1 °C. After mother retrieval, RNA biosynthesis decreased 27% and 34% in total brain cortex and in isolated neurons, respectively. This fall is proportional to the body temperature reduction and can be avoided placing the pups at 37 °C immediately after the separation. Rethermostatization of offsprings, after one hour at 25 °C, showed an overshoot of RNA biosynthesis (145%) with further stabilization of synthesis rates to normal levels after 100 min. This classical physiological mechanism was further studied in vitro. Comparing in vivo and in vitro experiments, it is concluded that overshooting can not be observed in vitro if temperature reduction was not previously performed in vivo. Thus, this phenomenon seems to respond to humoral factors in order to be triggered. Afterwards, in vitro overshooting following cold stress in vivo, demonstrates that the depressed tissue by itself has the capability to turn back to normal RNA levels in the same way as observed in vivo.