Glutamatergic lateral parabrachial neurons innervate orexin-containing hypothalamic neurons in the rat.
We performed this study to understand the anatomical substrates of parabrachial nucleus (PBN) modulation of orexin (ORX)-containing neurons in the hypothalamus. After biotinylated dextranamine (BDA) injection into the lateral PBN and immunostaining of ORX-containing neurons in the rat, the prominent overlap of the distribution field of the BDA-labeled fibers and that of the ORX-immunoreactive (ir) neurons was found in the lateralmost part of the dorsomedial nucleus and adjacent dorsal perifornical area (this overlapping field was referred to as "suprafornical area" in the present study), and the labeled axon terminals made asymmetrical synaptic contacts with somata and dendrites of the ORX-ir neurons. We further revealed that almost all the "suprafornical area"-projecting lateral PBN neurons were positive for vesicular glutamate transporter 2 mRNA and very few of them were positive for glutamic acid decarboxylase 67 mRNA. The present data suggest that ORX-containing neurons in the "suprafornical area" may be under the excitatory influence of the glutamatergic lateral PBN neurons probably for the regulation of arousal and waking.
Niu
Jian-Guo
JG
Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo 693-8501, Japan.
Yokota
Shigefumi
S
Tsumori
Toshiko
T
Qin
Yi
Y
Yasui
Yukihiko
Y
D000344:Afferent Pathways / Q000166:cytology / Q000502:physiology; D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D002772:Cholera Toxin / Q000378:metabolism; D003911:Dextrans / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D018698:Glutamic Acid / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D046529:Microscopy, Electron, Transmission; D009474:Neurons / Q000502:physiology* / Q000648:ultrastructure; D009479:Neuropeptides / Q000378:metabolism*; D000068797:Orexins; D011149:Pons / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure; D050599:Vesicular Glutamate Transport Protein 2 / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure
D003911:Dextrans; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D012333:RNA, Messenger; C493475:Slc17a6 protein, rat; D050599:Vesicular Glutamate Transport Protein 2; C076397:biotinylated dextran amine; D018698:Glutamic Acid; D001710:Biotin; D002772:Cholera Toxin; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1