サンテンダイ ゴダイ サンキ ニ ミエル カンザン セツワ ニツイテ

研究ノート(Note

ヘイアンキョウ ノ コウロカン ニカンスル イチコウサツ

After　the　last　visit　of　Bokkai（渤海）and　Tδtan（東丹）in　the　IOth　century，“Heiankyδ・K6rokan”，　which　was　the international　reception　hall　in　the　Japanese　capital　city　of　Heian，　lost　its　primary　allotment　of　duties．　Therefore，　there remain　few　historical　materials　about　Heianky6・K6rokan．　The　author　believes　that　some　former　studies　gave　a wrong　interpretation　of　the　materials． 　In　reexamining　those　materials，　the　author　came　to　the　following　conclusion：The　building　of　Heianky6－K6rokan was　on　the　wane　after　975　and　the　foundat量on　stones　of　Kδrokan　were　carried　away　in　102L　Since　then，　Kδrokan　has never　been　rβconstructed　in　the　capital　city　Heian，　but　the　place・name“K6rokan”remained　there　til1　the　15th　century

カチオジエンギ ニ ミエル ソウ カイショウ ニツイテ

論説(Article

Orexin Neurons Receive Glycinergic Innervations

Glycine, a nonessential amino-acid that acts as an inhibitory neurotransmitter in the central nervous system, is currently used as a dietary supplement to improve the quality of sleep, but its mechanism of action is poorly understood. We confirmed the effects of glycine on sleep/wakefulness behavior in mice when administered peripherally. Glycine administration increased non-rapid eye movement (NREM) sleep time and decreased the amount and mean episode duration of wakefulness when administered in the dark period. Since peripheral administration of glycine induced fragmentation of sleep/wakefulness states, which is a characteristic of orexin deficiency, we examined the effects of glycine on orexin neurons. The number of Fos-positive orexin neurons markedly decreased after intraperitoneal administration of glycine to mice. To examine whether glycine acts directly on orexin neurons, we examined the effects of glycine on orexin neurons by patch-clamp electrophysiology. Glycine directly induced hyperpolarization and cessation of firing of orexin neurons. These responses were inhibited by a specific glycine receptor antagonist, strychnine. Triple-labeling immunofluorescent analysis showed close apposition of glycine transporter 2 (GlyT2)-immunoreactive glycinergic fibers onto orexin-immunoreactive neurons. Immunoelectron microscopic analysis revealed that GlyT2-immunoreactive terminals made symmetrical synaptic contacts with somata and dendrites of orexin neurons. Double-labeling immunoelectron microscopy demonstrated that glycine receptor alpha subunits were localized in the postsynaptic membrane of symmetrical inhibitory synapses on orexin neurons. Considering the importance of glycinergic regulation during REM sleep, our observations suggest that glycine injection might affect the activity of orexin neurons, and that glycinergic inhibition of orexin neurons might play a role in physiological sleep regulation