Ionizing radiation as preconditioning against transient cerebral ischemia in XXXX .

@entity35 @entity1249 @entity16 @entity63
Induction of ischemic tolerance (IT), the ability of an organism to survive an otherwise lethal @entity63 , is the most effective known approach to preventing @entity16 . IT can be induced by exposing animals to a broad range of stimuli. In this study we tried to induce IT of brain neurons using ionizing radiation (IR). A preconditioning (pre-C) dose of 10, 20, 30 or 50 Gy of gamma rays was used 2 days before an 8 min @entity63 in adult male @entity35 . @entity63 alone caused the degeneration of almost one half of neurons in @entity1249 region of hippocampus. However, a significant decrease of the number of degenerating neurons was observed after higher doses of radiation (30 and 50 Gy). Moreover, @entity63 significantly impaired the spatial memory of @entity35 as tested in Morris's water maze. In @entity35 with a 50 Gy pre-C dose, the latency times were reduced to values close to the control level. Our study is the first to reveal that IR applied in sufficient doses can induce IT and thus allow pyramidal @entity1249 neurons to survive @entity63 . In addition, we show that the beneficial effect of IR pre-C is proportional to the radiation dose.
