| 研究実績の概要 |
Initially, this research project aimed to identify brain regions and signaling pathways underlying cannabinoid-induced seizures. Based on previous in-situ hybridization data we assumed that SO nucleus is involved in cannabinoid convulsive effects and therefore investigated the effect of optogenetic activation of SO nucleus. Unexpectedly, we discovered that bilateral photostimulation of SO nuclei did not induce electrographic seizures, but resulted in increased wakefulness (time in wake) with complete absence of sleep (both NREM and REM) during stimulation. Prolonged photostimulation (4 hours and more) resulted in complete absence of sleep and produced massive sleep rebound, accompanied by increased NREM sleep amount and delta NREM amount immediately after the end of stimulation. The other parameters, such as behavior or wake state analysis did not show any abnormality. We have also examined the effect of 8 hrs photostimulation, which resulted in the absence of sleep for the first 4 hours and significant decrease of sleep for the rest of photostimualtion time. This suggests that SO nucleus is strongly involved in inducing and possibly maintaining arousal state. To our knowledge this data has not been reported by anyone yet. In future, we are very interested to investigate how activation of SO nuclei produces arousal, what mechanism underlie this phenomenon and to anatomically dissect inputs and outputs of the structures causing the arousal effect.
|
