Abstract
Occipitocortical slices of rats were preincubated with [ 3H]noradrenaline or [ 3H]serotonin; striatal slices were preincubated with [ 3H]dopamine. The outflow of 3H-compounds was studied. In slices preincubated with [ 3H]noradrenaline, 1 nM amezinium diminished the outflow of deaminated metabolites (mainly [ 3H]-3,4-dihydroxyphenylglycol). Higher concentrations in addition released [ 3H]noradrenaline. The effects were antagonized by cocaine. In slices preincubated with [ 3H]dopamine, 1 nM amezinium caused no change, but 10 nM amezinium decreased the outflow of deaminated products (mainly [ 3H]-3,4-dihydroxyphenylacetic acid). Higher concentrations in addition released [ 3H]dopamine. The effects were antagonized by nomifensine. In experiments with [ 3H]serotonin, 1 nM amezinium caused no change, but 10 nM amezinium reduced the outflow of [ 3H]-5-hydroxyindoleacetic acid. Higher concentrations in addition released [ 3H]serotonin. The effects were antagonized by paroxetine. When amezinium was injected in vivo 1 hr before sacrifice, up to 10 mg/kg did not change the deamination of [ 3H]noradrenaline in cortical cubes; amezinium (50 mg/kg) caused slight inhibition. The results indicate that amezinium, added in vitro, is a very potent inhibitor of the MAO inside cerebral noradrenergic neurones. It is less potent at dopaminergic and serotonergic neurones. When injected systemically in vivo, however, amezinium at moderate doses has no effect on central monoamine catabolism, probably because of exclusion from the brain by the blood-brain barrier.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.