Dysregulated 5-HT2A receptor binding in postmortem frontal cortex of schizophrenic subjects

Carolina Muguruza, José L. Moreno, Adrienne Umali, Luis F. Callado, J. Javier Meana, Javier González-Maeso

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

Previous postmortem and neuroimaging studies have repeatedly suggested alterations in serotonin 5-HT2A receptor (5-HT2AR) binding associated with the pathophysiology of schizophrenia. These studies were performed with ligands, such as ketanserin, altanserin and LSD, that may bind with high-affinity to different structural or functional conformations of the 5-HT2AR. Interpretation of results may also be confounded by chronic antipsychotic treatment and suicidal behavior in the schizophrenia group. We quantified 5-HT2AR density by radioligand binding assays in postmortem prefrontal cortex of antipsychotic-free (n=29) and antipsychotic-treated (n=16) schizophrenics, suicide victims with other psychiatric diagnoses (n=13), and individually matched controls. [3H]Ketanserin binding, and its displacement by altanserin or the LSD-like agonist DOI, was assayed. Results indicate that the number of [3H]ketanserin binding sites to the 5-HT2AR was increased in antipsychotic-free (128±11%), but not in antipsychotic-treated (92±12%), schizophrenic subjects. In suicide victims, [3H]ketanserin binding did not differ as compared to controls. Aging correlated negatively with [3H]ketanserin binding in schizophrenia, suicide victims and controls. The fraction of high-affinity sites of DOI displacing [3H]ketanserin binding to the 5-HT2AR was increased in antipsychotic-free schizophrenic subjects. Functional uncoupling of heterotrimeric G proteins led to increased fraction of high-affinity sites of altanserin displacing [3H]ketanserin binding to the 5-HT2AR in schizophrenic subjects, but not in controls. Together, these results suggest that the active conformation of the 5-HT2AR is up-regulated in prefrontal cortex of antipsychotic-free schizophrenic subjects, and may provide a pharmacological explanation for discordant findings previously obtained.

Original languageEnglish
Pages (from-to)852-864
Number of pages13
JournalEuropean Neuropsychopharmacology
Volume23
Issue number8
DOIs
StatePublished - Aug 2013

Keywords

  • Postmortem human brain
  • Radioligand binding
  • Schizophrenia
  • Serotonin
  • Serotonin 5-HT2A receptor
  • Suicide

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