Abstract
The second messenger cGMP controls cardiovascular and gastrointestinal homeostasis in mammals. However, its physiological relevance in the nervous system is poorly understood.1 Now, we have reported that the cGMP-dependent protein kinase type I (PRKG1) is implicated in the regulation of the timing and quality of sleep and wakefulness.2 Prkg1 mutant mice showed altered distribution of sleep and wakefulness as well as reduction in rapid-eye-movement sleep (REMS) duration and in non-REMS consolidation. Furthermore, the ability to sustain waking episodes was compromised. These observations were also reflected in wheel-running and drinking activity. A decrease in electroencephalogram power in the delta frequency range (1–4 Hz) under baseline conditions was observed, which was normalized after sleep deprivation. Together with the finding that circadian clock amplitude is reduced in Prkg1 mutants these results indicate a decrease of the wake-promoting output of the circadian system affecting sleep. Because quality of sleep might affect learning we tested Prkg1 mutants in several learning tasks and find normal spatial learning but impaired object recognition memory in these animals. Our findings indicate that Prkg1 impinges on circadian rhythms, sleep and distinct aspects of learning.
Acknowledgements
We like to thank Rüdiger Klein for the Nes-Cre mice, and Anne-Marie Schönegge and Claudia Becker for help with behavioral testing. This research was supported by the DFG and VolkswagenStiftung (Robert Feil), the National Genome Research Network (NGFN), Foerderkennzeichen 01GR0430, and by EUMODIC, LSHG-CT-2006-037188 (Sabine M. Hölter and Wolfgang Wurst), the Dr. Karl Kuhn-Stiftung and fortüne-Programm der Medizinischen Fakultät der Universität Tübingen (grant #1774-0-0) (Susanne Feil), and the Swiss National Science Foundation, the State of Fribourg and EUCLOCK (Urs Albrecht).
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