title: Orexinergic innervation of the extended amygdala and basal ganglia in the rat.
abstract: The orexinergic system interacts with several functional states of emotions, stress, hunger, wakefulness and behavioral arousal through four pathways originating in the lateral hypothalamus (LH). Hundreds of orexinergic efferents have been described by tracing studies and direct immunohistochemistry of orexin in the forebrain, olfactory regions, hippocampus, amygdala, septum, basal ganglia, thalamus, hypothalamus, brain stem and spinal cord. Most of these tracing studies investigated the whole orexinergic projection to all regions of the intracranial part of the CNS. To identify the orexinergic efferents at the subnuclear level of resolution, we focussed on the orexinergic target in the amygdala, which is substantially involved in the LH output and contributes mostly to the functional outcome of the orexinergic system and the basal ganglia. Immunohistochemical identification of axonal orexin A and orexin B in male adult rats has been performed on serial sections. In the extended amygdala many new orexinergic targets were found in the anterior amygdaloid area (dense), anterior cortical nucleus (moderate), amygdalostriatal transition region (moderate), basolateral regions (moderate), basomedial nucleus (moderate), several bed nucleus of the stria terminals regions (few to dense), central amygdaloid subdivisions (dense), posteromedial cortical nucleus (moderate) and medial amygdaloid subnuclei (dense). Furthermore, the entopeduncular nucleus has been newly identified as another target for orexinergic fibers with a high density. These results suggest that subdivisions and subnuclei of the extended amygdala are specific targets of the orexinergic system.
authors.affiliation: Institute of Anatomy, University of Rostock, P. O. Box 100888, 18055, Rostock, Germany. schmitt@med.uni-rostock.de
authors.forename: Oliver
authors.initials: O
authors.lastname: Schmitt
authors.forename: Kamen G
authors.initials: KG
authors.lastname: Usunoff
authors.forename: Nikolai E
authors.initials: NE
authors.lastname: Lazarov
authors.forename: Dimitar E
authors.initials: DE
authors.lastname: Itzev
authors.forename: Peter
authors.initials: P
authors.lastname: Eipert
authors.forename: Arndt
authors.initials: A
authors.lastname: Rolfs
authors.forename: Andreas
authors.initials: A
authors.lastname: Wree
mesh_terms: D000679:Amygdala / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D001479:Basal Ganglia / Q000166:cytology / Q000378:metabolism*; D022081:Cell Surface Extensions / Q000378:metabolism / Q000648:ultrastructure; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D009434:Neural Pathways / Q000166:cytology* / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D000068797:Orexins; D051381:Rats; D017208:Rats, Wistar
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins