Behavioral state-dependent change of dendrodendritic synaptic inhibition in the rat olfactory bulb

Behavioral states regulate how information is processed in local neuronal circuits. Here I asked whether dendrodendritic synaptic interactions in the olfactory bulb vary with brain and behavioral states. To examine the state-dependent change of the dendrodendritic synaptic transmission, I monitored changes in field potential responses in the olfactory bulb of urethane-anesthetized and freely behaving rats. In urethane-anesthetized rats, granule-to-mitral dendrodendritic synaptic inhibition was larger and longer when slow waves were present in the electroencephalogram (slow-wave state) than during the fast-wave state. The state-dependent alternating change in the granule-to-mitral inhibition was regulated by the cholinergic system. In addition, the frequency of the spontaneous oscillatory activity of local field potentials and periodic discharges of mitral cells in the olfactory bulb shifted in synchrony with shifts in the neocortical brain state. Freely behaving rats showed multilevel changes in dendrodendritic synaptic inhibition that corresponded to diverse behavioral states; the inhibition was the largest during slow-wave sleep state, and successively smaller during light sleep, awake immobility, and awake moving states. These results provide evidence that behavioral state–dependent global changes in cholinergic tone modulate dendrodendritic synaptic inhibition and the information processing mode in the olfactory bulb報告番号: 甲24774 ; 学位授与年月日: 2009-03-23 ; 学位の種別: 課程博士 ; 学位の種類: 博士(医学) ; 学位記番号: 博医第3194号 ; 研究科・専攻: 医学系研究科機能生物学専