title: Synaptic contacts of substance P-immunoreactive axon terminals in the nucleus tractus solitarius onto neurons projecting to the caudal ventrolateral medulla oblongata in the rat.
abstract: The possibility that substance P (SP)-immunoreactive axon terminals in the nucleus tractus solitarius (NTS) make synaptic contacts onto NTS neurons projecting to the catecholaminergic cell region in the caudal ventrolateral medulla oblongata (CVLM) was examined in the rat using a retrograde tract-tracing method combined with immunohistochemistry. After injection of a retrograde tracer, wheat germ agglutinin-conjugated horseradish peroxidase-colloidal gold complex (WGA-HRP-gold), into the CVLM region where tyrosine hydroxylase-immunoreactive neurons were situated, many retrogradely labeled neurons were detected in the dorsal parts of the NTS, especially at levels between 1.0 mm caudal and 0.5 mm rostral to the obex. Immunoelectron microscopy revealed synaptic contacts between SP-immunoreactive axon terminals and WGA-HRP-gold-labeled neurons in the NTS. These findings indicated that SP regulates NTS neurons which project to the catecholaminergic cell region of the CVLM.
authors.affiliation: Department of Anatomy, Saga Medical School, Japan. kawanoh@post.saga-med.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Kawano
authors.forename: S
authors.initials: S
authors.lastname: Masuko
mesh_terms: D000818:Animals; D001370:Axonal Transport; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure*; D006046:Gold; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000033:anatomy & histology / Q000502:physiology*; D008854:Microscopy, Electron; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017552:Solitary Nucleus / Q000033:anatomy & histology / Q000502:physiology*; D013373:Substance P / Q000032:analysis*; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure*; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
chemical_list: D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D013373:Substance P; D006046:Gold