Quantitative distribution of rat brain monoamine oxidase A by [14C]clorgyline autoradiography.
The distribution of functionally active monoamine oxidase type A (MAO-A) was investigated by in vivo quantitative autoradiography using [14C]clorgyline in normal, conscious rat brain. [14C]clorgyline was synthesized by the methylation reaction of N-desmethylclorgyline using [14C]methyliodide. Sixty minutes after [14C]clorgyline administration (1.58 MBq/animal i.v.), the brains were removed and prepared for autoradiography by washing the brain sections with 5% trichloroacetic acid solution to remove the nonbinding free tracer. The amount of MAO-A was calculated from the regional acid-insoluble tissue radioactivity and the specific activity of the tracer. The highest amount of MAO-A (5.84 nmol/g tissue) was found in the locus coeruleus. The interpeduncular nucleus, habenular nucleus, fasciculus retroflexus, and solitary tract nucleus possessed over 1.6 nmol/g tissue of MAO-A. Among 23 regions of interest, the lowest amount of MAO-A (0.37 nmol/g tissue) was found in the globus pallidus. The findings of this study suggest that the pattern of MAO-A parallels both in neuroanatomical distribution and in density that of norepinephrine and serotonin innervation. The MAO-A concentration was, however, relatively low in the dopamine-related areas. This corresponded to the previous results obtained by histochemical analysis. In addition, among the white matter structures, a high amount of MAO-A was found specifically in the fasciculus retroflexus.
Kondoh
Y
Y
Department of Neurology, Research Institute for Brain and Blood Vessels-Akita, Japan.
Murakami
M
M
Yin
W
W
Mizusawa
S
S
Nakamichi
H
H
Nagata
K
K
D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000033:anatomy & histology* / Q000187:drug effects / Q000201:enzymology*; D003010:Clorgyline; D007553:Isotope Labeling; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012642:Selegiline / Q000494:pharmacology
D012642:Selegiline; D008995:Monoamine Oxidase; D003010:Clorgyline