[Variations of @entity1640 and cortical @entity2918 and XXXX reveal transitions in arousal states: microdialysis study in the rat].

@entity1640 @entity935 @entity1421 @entity2918 @entity3009 @entity2339 @entity750 @entity1154 @entity2661
Brain microdialysis coupled with EEG recording allowed us to track dynamic neurochemical changes every 3 or 6 minutes in relation to sleep/wake cycles. We chose to investigate @entity2918 (PG) and @entity1154 ( @entity2661 , @entity750 and metabolites) because of their respective role in the states of vigilance, mainly suggested by pharmacological approaches, and because of the known interactions between PGs and @entity1154 . We focused on the paraventricular and ventromedial nuclei of the @entity2339 for their involvement in the relationships between feeding, metabolic rate and sleep, and the prefrontal cortex for its role in vigilance. These studies revealed a few changes in @entity3009 or @entity1154 levels as a function of a given state of vigilance. In particular, @entity750 levels were higher during wakefulness than during sleep in both @entity2339 and cortex. Both @entity1640 and cortical @entity1421 levels were higher during wakefulness than during slow wave sleep and still higher during paradoxical sleep in the cortex. Cortical PGD2 showed an exactly reverse profile of @entity1421 . These changes are in agreement with the described awaking action of @entity1421 and with the hypnogenic action of PGD2. Our most informative findings were the sequential changes around transitions from one state to another that allow to predict the moment of onset of both sleep and wakefulness. Both in @entity2339 and in cortex, ondulatory patterns of @entity1421 were encountered around the transitions between states. @entity1421 was high in the middle of wakefulness, then regularly dropped announcing the occurrence of sleep, where the drop persisted before giving place to a rise in prediction to the next period of wakefulness. A similar profile was also observed for cortical @entity750 , but its low levels reached a plateau during sleep. Cortical @entity935 levels showed sudden and dramatic drops during short periods of wakefulness closely surrounding slow wave sleep. In some instances, as in the case of @entity1421 , similar profiles of variations could be found both in the @entity2339 and cortex. But in most cases, different and even opposite profiles were encountered in those two structures. Interestingly, in some instances, the pattern of changes in both @entity2918 and @entity1154 were similar, as for example between @entity1640 @entity1421 and @entity935 as well as between cortical @entity1421 and @entity750 . These similarities support the idea of the suggested interaction between @entity2918 and @entity1154 , in particular concerning their involvement in the regulation of sleep/wake cycles.
