BACKGROUND: Mitogen-activated protein kinases (MAPKs) is a group of protein kinase related with neuronal apoptosis. Sleep derivation can lead to neuronal apoptosis.OBJECTIVE: To observe change and possible significance of MAPKs in rats after sleep deprivation.DESIGN: Prospective study with complete randomization.SETTING:Research Room of Nerve, Department of Physiology, Zhengzhou University.MATERIALS: The experiment was performed at Zhengzhou University from June 2000 to October 2002. Totally 24 adult healthy SD rats were selected.METHODS: A total of 24 rats were randomly assigned into rapid eye movement (REM) sleep deprivation group, REM sleep deprivation control group and normal control group with 8 rats in each group. The rats in the sleep deprivation group received successive sleep deprivationfor 72 hours from 8:00in the morning. The rats in the normal control group were fed in the rearing cage, having normal sleep-awareness cycle. Their morphological change was observed. Another 24 rats were grouped as above and determined with MAPKs. Morphological change of neurons in hippocampus of rats after sleep deprivation was observed with terminal dUTP nick end-labelling (TUNEL)staining. Changes of activity of extracellular signal-regulated kinase (ERK)and expression of c-Jun N-terminal kinase (JNK) were observed.MAIN OUTCOME MEASURES: ①Morphological change of hippocampal neuron in rats after sleep derivation was observed. ②Changes of expressions of ERK and JNK in hippocampal neuron were observed.RESULTS: ①Morphological change of hippocarnpal neuron: A mass of apoptotic positive cells appeared in CA1 and CA3 regions of rats in the REM sleep deprivation group, mainly distributed in pyramidal layer of hippocampus. A few apoptotic cells appeared in CA2 region. Seldom apoptotic cells appeared in the CA4 region. There was no significant positive cell in hippocampal tissue sections of the normal control group and REM sleep deprivation control group. ②Change of ERK activity: It was significantly lower in the REM sleep deprivation group than the REM sleep deprivation control group and normal control group (1 764.00±941.56,6 139.67±2 863.62,566.700±2 763.41 ,t=3.211 1,0.986 3,P ＜ 0.05). ③JNK positive expression: It was markedly higher in the REM sleep deprivation group than the REM sleep deprivation control group and normal control group (87.5%, 25%, 75%, t=3.412 1, P＜0.05).CONCLUSION: The sleep deprivation can cause change of MAPKs activity, which may be related with neuron apoptosis.

AIM: To explore the change and the possible role of MAPKs in rat hippocampus neuron after sleep deprivation. METHODS: The morphology of hippocampus neuron after sleep derivation was observed by TUNEL and HE staining, the activity of ERK was assayed by ?-liquid scintillation counting and the expression of JNK was detected by Western blot. RESULTS: In paradoxical sleep deprivation (PSD) group, the number of apoptotic cells in hippocampus was increased. The scores of ERK activity were (1 764.00)?941.56. Compared with control groups, the ERK activity was obviously decreased (P