Serotonin 5-HT2A receptor expression and functionality in postmortem frontal cortex of subjects with schizophrenia: Selective biased agonism via Gαi1-proteins

Aintzane García-Bea, Patricia Miranda-Azpiazu, Carolina Muguruza, Sara Marmolejo-Martinez-Artesero, Rebeca Diez-Alarcia, Ane M. Gabilondo, Luis F. Callado, Benito Morentin, Javier González-Maeso, J. Javier Meana

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Serotonin 5-HT2A receptors (5-HT2ARs) have been implicated in schizophrenia. However, postmortem studies on 5-HT2ARs expression and functionality in schizophrenia are scarce. The 5-HT2AR mRNA and immunoreactive protein expression were evaluated in postmortem tissue from dorsolateral prefrontal cortex (DLPFC) of antipsychotic-free (n = 18) and antipsychotic-treated (n = 9) subjects with schizophrenia, and matched controls (n = 27). Functional coupling of 5-HT2AR to G-proteins was tested by measuring the activation induced by the agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride ((±)DOI) in antibody-capture [35S]GTPγS scintillation proximity assays (SPA). In antipsychotic-free schizophrenia subjects, 5-HT2AR mRNA expression and protein immunoreactivity in total homogenates was similar to controls. In contrast, in antipsychotic-treated schizophrenia subjects, lower mRNA expression (60±9% vs controls) and a trend to reduced protein immunoreactivity (86±5% vs antipsychotic-free subjects) just in membrane-enriched fractions was observed. [35S]GTPγS SPA revealed a significant ~6% higher stimulation of Gαi1-protein by (±)DOI in schizophrenia, whereas activation of the canonical Gαq/11-protein pathway by (±)DOI remained unchanged. Expression of Gαi1- and Gαq/11-proteins did not differ between groups. Accordingly, in rats chronically treated with clozapine, but not with haloperidol, a 30–40% reduction was observed in 5-HT2AR mRNA expression, 5-HT2AR protein immunoreactivity and [3H]ketanserin binding in brain cortical membranes. Overall, the data suggest a supersensitive 5-HT2AR signaling through inhibitory Gαi1-proteins in schizophrenia. Together with previous results, a dysfunctional pro-hallucinogenic agonist-sensitive 5-HT2AR conformation in postmortem DLPFC of subjects with schizophrenia is proposed. Atypical antipsychotic treatment would contribute to counterbalance this 5-HT2AR supersensitivity by reducing receptor expression.

Original languageEnglish
Pages (from-to)1453-1463
Number of pages11
JournalEuropean Neuropsychopharmacology
Volume29
Issue number12
DOIs
StatePublished - Dec 2019
Externally publishedYes

Keywords

  • Antipsychotics
  • G protein
  • Human brain
  • Schizophrenia
  • Serotonin 2A receptor

Fingerprint

Dive into the research topics of 'Serotonin 5-HT2A receptor expression and functionality in postmortem frontal cortex of subjects with schizophrenia: Selective biased agonism via Gαi1-proteins'. Together they form a unique fingerprint.

Cite this