title: Ultrastructural evidence for an olfactory-autonomic pathway through the rat central amygdaloid nucleus.
abstract: The innervation of medullary projection neurons in the central amygdaloid nucleus (Ce) by afferents from the ventral taenia tecta (VTT) was investigated using combined lesion-induced axonal degeneration and retrograde transport of horseradish peroxidase-conjugated wheat germ agglutinin (HRP-WGA). Injections of HRP-WGA into the nucleus tractus solitarii resulted in retrograde labeling of neurons in the medial Ce. Ultrastructurally HRP-WGA reaction product was identifiable in the perikarya and proximal dendrites of Ce neurons. Degenerating terminals, probably due to damage at the HRP-WGA injection site, were few and confined to the ventral Ce. Electrolytic coagulation of the VTT resulted in approximately 9% of terminals in medial Ce showing signs of degeneration at 5 days post-lesion. Of the terminals sampled, slightly more than 40% were in contact with the dendrites of retrogradely labeled neurons. Where evident, these terminals formed exclusively symmetrical synaptic contacts. These data provide evidence for an oligosynaptic olfactory-autonomic pathway in the rat that may mediate olfactory influences on gastric and cardiovascular aspects of autonomic function.
authors.affiliation: Department of Anatomy, University of Iowa, Iowa City 52245.
authors.forename: M D
authors.initials: MD
authors.lastname: Cassell
authors.forename: L
authors.initials: L
authors.lastname: Roberts
mesh_terms: D000679:Amygdala / Q000648:ultrastructure*; D000818:Animals; D001341:Autonomic Nervous System / Q000648:ultrastructure*; D003712:Dendrites / Q000648:ultrastructure; D006735:Horseradish Peroxidase; D066298:In Vitro Techniques; D008297:Male; D008526:Medulla Oblongata / Q000648:ultrastructure; D009410:Nerve Degeneration / Q000502:physiology; D009474:Neurons / Q000648:ultrastructure; D009833:Olfactory Pathways / Q000648:ultrastructure*; D016548:Prosencephalon / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins
chemical_list: D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins; D006735:Horseradish Peroxidase