Agonist Binding to α2-Adrenoceptors Is Elevated in the Locus Coeruleus from Victims of Suicide

Authors

  • Gregory A. Ordway,

    Corresponding author
    1. Departments of Psychiatry and Human Behavior, and Pharmacology, University of Mississippi Medical Center, Jackson, Mississippi; and
    2. Department of Psychiatry, Case Western Reserve University; Cleveland, Ohio, U.S.A.
      Address correspondence and reprint requests to Dr. G. A. Ordway at Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, U.S.A.
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  • Peter S. Widdowson,

    1. Department of Psychiatry, Case Western Reserve University; Cleveland, Ohio, U.S.A.
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  • Karen Streator Smith,

    1. Department of Psychiatry, Case Western Reserve University; Cleveland, Ohio, U.S.A.
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  • Angelos Halaris

    1. Departments of Psychiatry and Human Behavior, and Pharmacology, University of Mississippi Medical Center, Jackson, Mississippi; and
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  • Portions of this article were presented at the annual meeting of the American College of Neuropsychopharmacology in San Juan, Puerto Rico, on December 31, 1991.

Address correspondence and reprint requests to Dr. G. A. Ordway at Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, U.S.A.

Abstract

Abstract: The binding of an agonist, p-[125I]iodoclonidine, and an antagonist, [3H]yohimbine, to α2-adrenoceptors was measured autoradiographically in the locus coeruleus from 10 pairs of antidepressant-free victims of suicide and age-matched controls. Agonist binding to α2-adrenoceptors was significantly greater in the locus coeruleus from victims of suicide compared with control subjects. In contrast, antagonist binding to α2-adrenoceptors in the locus coeruleus did not differ significantly between control and suicide subjects. HPLC analysis of norepinephrine in tissue sections of the locus coeruleus did not reveal any differences between control subjects and suicide victims, suggesting that differences in agonist binding are not a result of differences in retention of the endogenous agonist norepinephrine in tissue sections. The increase in agonist binding to α2-adrenoceptors in the locus coeruleus of victims of suicide links an altered expression of the high-affinity state of autoinhibitory α2-adrenoceptors with suicide.

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