Autoradiographic Demonstration of Increased α2-Adrenoceptor Agonist Binding Sites in the Hippocampus and Frontal Cortex of Depressed Suicide Victims

Authors

  • Antonio M. González,

    1. Unit of Pharmacology, Department of Physiology and Pharmacology, and
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  • Julio Pascual,

    1. Unit of Pharmacology, Department of Physiology and Pharmacology, and
    2. Department of Medicine, University of Cantabria Medical School, Santander;
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  • J. Javier Meana,

    1. Section of Pharmacology, Department of Neurosciences, University of the Basque Country Medical School, Leioa; and
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  • Fernando Barturen,

    1. Section of Pharmacology, Department of Neurosciences, University of the Basque Country Medical School, Leioa; and
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  • Carmen Del Arco,

    1. Unit of Pharmacology, Department of Physiology and Pharmacology, and
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  • Angel Pazos,

    1. Unit of Pharmacology, Department of Physiology and Pharmacology, and
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  • Jesús A. García-Sevilla

    Corresponding author
    1. Section of Pharmacology, Department of Neurosciences, University of the Basque Country Medical School, Leioa; and
    2. Laboratory of Neuropharmacology, Department of Fundamental Biology and Health Sciences, University of the Balearic Islands, Palma de Mallorca, Spain
      Address correspondence and reprint requests to Dr. J. A. García-Sevilla at Lab. Neurofarmacologia, Dept. Biologia Fonamental i Ciències de la Salut, Universitat de les Illes Balears, Cra. Valldemossa Km 7.5, E-07071 Palma de Mallorca (Balears), Spain.
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  • Dedicated to Daniel X. Freedman, in memoriam.

Address correspondence and reprint requests to Dr. J. A. García-Sevilla at Lab. Neurofarmacologia, Dept. Biologia Fonamental i Ciències de la Salut, Universitat de les Illes Balears, Cra. Valldemossa Km 7.5, E-07071 Palma de Mallorca (Balears), Spain.

Abstract

Abstract: To examine directly in the brain the status of α2-adrenoceptors in major depression, the specific binding of the agonist [3H]UK 14304 was measured by quantitative receptor autoradiography in the hippocampus and frontal cortex of suicide victims (n = 17) with a retrospective diagnosis of depression (n = 7) or other psychiatric disorders (n = 10) as well as of matched control subjects (n = 9). In suicide victims, a significant increase in the number of α2-adrenoceptors was found in the CA1 field (40%) and dentate gyrus (20%) of the hippocampus and in the external layers I (33%) and II (31%) of the frontal cortex, compared with that in matched controls. In depressed suicide victims, the increase in α2-adrenoceptors in the CA1 field (57%) was significantly greater (24%, p < 0.05) than that observed in the group of suicide victims with other diagnoses (26%). In the same depressed suicide victims, the increase in cortical α2-adrenoceptors was restricted to layer I (34%) and it was equivalent to that found in layer I (33%) of suicide victims with other diagnoses. The results indicate that suicide is associated with increases in the high-affinity state of brain α2-adrenoceptors and that there is a pronounced localized increase of this inhibitory receptor in the hippocampus of depressed suicide victims.

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