Imidazoline receptors and human brain disorders

Ann N Y Acad Sci. 1999 Jun 21:881:392-409. doi: 10.1111/j.1749-6632.1999.tb09388.x.


Major depression, opioid addiction, neurodegenerative diseases, and glial tumors are associated with disturbances of imidazoline receptors (IR) in the human brain. In depression, the level of a 45-kD IR protein (putative I1-IR) is increased in the brain of suicide victims (51%) and in platelets of depressed patients (40%). The density of platelet I1-IR ([125I]-p-iodoclonidine binding) is also increased in depression (135%). The 29/30-kD IR protein (putative I2B-IR) is downregulated (19%) in suicide victims in parallel with a reduction (40%) in the density of I2B-IR ([3H]idazoxan binding). Antidepressant drugs induce downregulation of 45-kD IR protein and I1-sites in platelets of depressed patients and upregulation of I2-sites in rat brain. The densities of I2B-IR and the related 29/30-kD IR protein are decreased (39% and 28%) in the brain of heroin addicts. The density of I2B-IR is increased in Alzheimer's disease (63%) and decreased in Huntington's disease (56%). Brain I2B-IR is not altered in Parkinson's disease. The level of I2-IR in glial tumors is increased (two-fivefold) in parallel with the abundance of the related 29/30-kD IR protein (39%), whereas the level of 45-kD IR protein is decreased (39%). The possible functional relevance of these findings in the context of the pathogenesis of these disorders remains to be elucidated.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Alcoholism / metabolism
  • Animals
  • Blood Platelets / metabolism
  • Brain / metabolism*
  • Brain Diseases / metabolism*
  • Brain Neoplasms / metabolism
  • Depressive Disorder / metabolism
  • Humans
  • Imidazoline Receptors
  • Neurodegenerative Diseases / metabolism
  • Opioid-Related Disorders / metabolism
  • Rats
  • Receptors, Drug / genetics
  • Receptors, Drug / metabolism*
  • Suicide


  • Imidazoline Receptors
  • Receptors, Drug