Densities of I2-imidazoline receptors, alpha 2-adrenoceptors and monoamine oxidase B in brains of suicide victims.
In the frontal cortex of suicide victims, the density of I2-imidazoline receptors labeled by [3H]idazoxan was lower (40%) than that in healthy subjects. In the same brains, the immunoreactivity of a 29/30 kDa imidazoline receptor protein was also found to be significantly decreased (19%) and it showed a positive correlation with the density of I2-imidazoline receptors. Also in the same brains, the density of alpha 2-adrenoceptor antagonist binding sites labeled by [3H]RX821002 (2-methoxy idazoxan) was found to be unchanged. The density of brain I2-imidazoline receptors, correlated with aging in control subjects but not in suicides. The density of brain MAO-B sites labeled by [3H]Ro 19-6327 (lazabemide) in suicides was no different to that in age-matched controls. As expected the density of brain MAO-B sites in suicides showed a positive correlation with age, but it did not correlate with the density of I2-imidazoline receptors in the same brains. The data indicate that the I2-imidazoline receptors labeled by [3H]idazoxan in the brain of suicides is related to a 29/30 kDa imidazoline receptor protein identified by immunoblot analysis. The data also indicate that the brain I2-imidazoline receptor cannot be identified with the MAO-B isoenzyme. The decreased density of I2-imidazoline receptors in the brain of suicide victims might play a role in the pathogenesis of major depression.
Sastre
M
M
Department of Fundamental Biology and Health Sciences, University of the Balearic Islands, Palma de Mallorca, Spain.
García-Sevilla
J A
JA
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001921:Brain / Q000378:metabolism*; D005260:Female; D006801:Humans; D019329:Idazoxan / Q000031:analogs & derivatives / Q000378:metabolism; D054755:Imidazoline Receptors; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000032:analysis / Q000378:metabolism*; D011955:Receptors, Drug / Q000032:analysis / Q000378:metabolism*; D013405:Suicide; D014316:Tritium
D000317:Adrenergic alpha-Antagonists; D054755:Imidazoline Receptors; D011942:Receptors, Adrenergic, alpha; D011955:Receptors, Drug; D014316:Tritium; C058525:2-methoxyidazoxan; D008995:Monoamine Oxidase; D019329:Idazoxan