title: Densities of serotonergic projections as revealed by in situ synthesised labelled α-methyl-serotonin: an autoradiographic evaluation.
abstract: An estimate of serotonergic innervation density and regional serotonin (5-HT) concentration was performed from the distribution of in situ produced labelled α-methyl-serotonin. Rats were injected with ((3)H) labelled α-methyl-L: -tryptophan and the tracer distribution was measured using the autoradiographic method 14 days following the injection. In a separate experiment, the total brain concentration of 5-HT in the rat brain was found to be 2.4 ± 0.2 nmol/g. Based on this, and the assumption that the specific activity of in situ produced α-methyl-serotonin is the same as that of the injected tracer, it was possible to estimate the regional concentrations of 5-HT and the relative concentration of regional serotonergic innervations. It was found, and reported for the first time here, that the highest concentration of serotonergic innervation is present in the solitary nucleus. Regionally measured 5-HT concentrations accord well with previously reported concentrations of 5-HT.
authors.affiliation: Cone Laboratory For Neurosurgical Research, Montreal Neurological Institute, and Department of Neurology and Neurosurgery, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Nishi
authors.forename: Sho
authors.initials: S
authors.lastname: Takahashi
authors.forename: Mirko
authors.initials: M
authors.lastname: Diksic
mesh_terms: D000818:Animals; D001345:Autoradiography / Q000379:methods*; D001921:Brain / Q000033:anatomy & histology* / Q000378:metabolism*; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000031:analogs & derivatives* / Q000378:metabolism*; D014364:Tryptophan / Q000737:chemistry / Q000378:metabolism
chemical_list: C042390:alpha-methylserotonin; D012701:Serotonin; D014364:Tryptophan