ArticlesReduction but not cleavage of poly(ADP-ribose) polymerase during stress-mediated cell death in the rat hippocampusYun, Su-Jin; Lee, Doo-Jae; Kim, Mi-Ok; Jung, Bomi; Kim, Sung Ok; Sohn, Nak Won; Lee, Eunjoo H.CAAuthor Information Graduate School of East-West Medical Science, Kyung Hee University,Yong-In 449–701, Korea CACorresponding Author: [email protected] Received 12 December 2002; accepted 30 January 2003 NeuroReport: May 23rd, 2003 - Volume 14 - Issue 7 - p 935-939 doi: 10.1097/01.wnr.0000074340.81633.f1 Buy Metrics Abstract Sustained stress induces neuronal atrophy and death, especially in the hippocampus, which impairs hippocampal function. However, underlying mechanisms of stress-induced neuronal damage have not been precisely defined.We analyzed the molecular events related to apoptosis in the hippocampus of rats exposed to immobilization stress. Terminal dUTP nick end-labeling exhibited positive nuclei in the hippocampus of stressed rats, indicating DNA fragmentation. RT-PCR and Western blot analyses showed that immobilization stress increased and decreased the expression of pro-apoptotic gene bax and anti-apoptotic bcl-2 genes, respectively. Western blot analysis demonstrated that the characteristic 85 kDa apoptotic fragment of poly(ADP-ribose) polymerase (PARP) was not observed in the hippocampus subjected to immobilization stress. The amount of PARP protein was significantly reduced following stress. This study may provide a novel insight into molecular mechanisms implicated in hippocampal damage associated with stress. NeuroReport 14:935–939 © 2003 Lippincott Williams & Wilkins. © 2003 Lippincott Williams & Wilkins, Inc.