title: Neurokinin A coexists with substance P and serotonin in ventral medullary spinally projecting neurons of the rat.
abstract: The coexistence of neurokinin A (NKA) with substance P (SP) and serotonin (5-HT) in ventral medullary neurons of the parapyramidal region and nucleus raphe pallidus of the rat was studied using multiple immunofluorescence labeling. Nearly all of the NKA-immunoreactive (IR) cells in the parapyramidal region and raphe pallidus were SP-IR nd 5-HT-IR, whereas about 70% of the SP-IR neurons and about 60% of the 5-HT-IR neurons contained NKA-IR. There were no apparent differences in the patterns of coexistence between parapyramidal and raphe pallidus neurons. NKA-IR neurons, which colocalized SP-IR and 5-HT-IR, were studied for projections to the lumbar and thoracic spinal cord by use of retrograde transport of fluorescent tracer. Whereas about 50% of the retrogradely labeled neurons of the parapyramidal region and raphe pallidus contained NKA-IR, nearly all of the NKA-IR neurons projected to the thoracic and lumbar spinal cord. In addition, some NKA-IR neurons in the ventral medulla were retrogradely labeled with tracer from localized injections into the thoracic intermediolateral cell column. In summary, this study demonstrated that NKA-IR is colocalized with SP-IR in bulbospinal serotonergic neurons of the parapyramidal region and raphe pallidus, which are known to regulate sensory, motor, and autonomic activities of the spinal cord.
authors.affiliation: Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
authors.forename: K
authors.initials: K
authors.lastname: Nevin
authors.forename: H
authors.initials: H
authors.lastname: Zhuo
authors.forename: C J
authors.initials: CJ
authors.lastname: Helke
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000033:anatomy & histology / Q000737:chemistry*; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000737:chemistry; D015288:Neurokinin A / Q000276:immunology / Q000302:isolation & purification*; D009474:Neurons / Q000737:chemistry*; D011712:Pyramidal Tracts / Q000737:chemistry; D011903:Raphe Nuclei / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000276:immunology / Q000302:isolation & purification*; D013373:Substance P / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D012701:Serotonin; D013373:Substance P; D015288:Neurokinin A