Electrically induced release of [3H]dopamine from slices obtained from different rat brain cortex regions. Evidence for a widespread dopaminergic innervation of the neocortex

摘要: Abstract Slices obtained from the deeper layers of rat dorsal frontal, parietal and occipital brain cortex were incubated in vitro with6.25 × 10−7M [3H]dopamine (DA), subsequently superfused electrically stimulated, while held on quick transfer electrodes, changes efflux of3H individual amines measured. The separation amines, with quantitative recoveries, was performed by chromatography cation-exchange resins eluted sequentially water,1 NHCl 6 M urea in1 N HCl. When no drugs used, prestimulation entirely formed deaminated metabolites, following stimulation there an increase considerable amounts [3H]-noradrenaline (NA) now appeared. No DA present pre- or poststimulation medium. Similar results all regions studied. slices with10−5M desmethylimipramine (DMI),10−4M nialamide 10−4M tropolone, before during incubation [3H]DA, it observed that, prior to stimulation, composed 3-methoxytyramine (MTA), electrical stimulus increased release DA, NA compounds (in order decreasing release), change that MTA evident. stimulus-induced greatest frontal slices, intermediate parietal, lowest ones. DMI-resistant uptake [3H]DA also diminished when passing occipital. These findings are interpreted as due presence dopaminergic axon terminals studied, but a density diminishes rostrocaudal direction.