title: Bulbospinal neurons of the cat that co-contain serotonin and methionine enkephalin.
abstract: The present study utilizes a combined retrograde transport of Fast Blue (or rhodamine-labeled latex microspheres) and simultaneous immunofluorescence technique to demonstrate directly the coexistence of serotonin and methionine enkephalin in bulbospinal neurons of the cat. The bulbospinal neurons that immunostained for both serotonin and enkephalin were observed, without any distinct somatotopic organization, in the nuclei raphe pallidus, obscurus and magnus. They were also observed in the nucleus reticularis magnocellularis and the ventrolateral medulla (cell group B1/3). Among the bulbospinal neurons encountered within individual 5-HT-rich medullary nuclei, high proportions of these neurons co-containing serotonin and methionine enkephalin were evidenced in the nucleus raphe obscurus (64%) and nucleus raphe pallidus (56%), less so in cell group B1/3 (41%), nucleus raphe magnus (39%), and the nucleus reticularis magnocellularis (29%). Physiological significance of such a morphological substrate is discussed.
authors.affiliation: Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164-6520.
authors.forename: S J
authors.initials: SJ
authors.lastname: Fung
authors.forename: V K
authors.initials: VK
authors.lastname: Reddy
authors.forename: H
authors.initials: H
authors.lastname: Zhuo
authors.forename: R H
authors.initials: RH
authors.lastname: Liu
authors.forename: C D
authors.initials: CD
authors.lastname: Barnes
mesh_terms: D000578:Amidines; D000818:Animals; D001370:Axonal Transport; D015415:Biomarkers; D001931:Brain Mapping; D001933:Brain Stem / Q000737:chemistry / Q000166:cytology; D002415:Cats; D004525:Efferent Pathways; D004744:Enkephalin, Methionine / Q000032:analysis*; D005260:Female; D005455:Fluorescent Antibody Technique; D008297:Male; D008863:Microspheres; D009046:Motor Neurons / Q000737:chemistry*; D011903:Raphe Nuclei / Q000166:cytology / Q000502:physiology*; D012235:Rhodamines; D012701:Serotonin / Q000032:analysis*; D013116:Spinal Cord / Q000737:chemistry / Q000166:cytology*
chemical_list: D000578:Amidines; D015415:Biomarkers; D012235:Rhodamines; C031455:diamidino compound 253-50; D012701:Serotonin; D004744:Enkephalin, Methionine