Clozapine markedly elevates pregnenolone in rat hippocampus, cerebral cortex, and serum: candidate mechanism for superior efficacy?

Journal Article

Clozapine demonstrates superior efficacy in patients with schizophrenia, but the precise mechanisms contributing to this clinical advantage are not clear. Clozapine and olanzapine increase the GABAergic neuroactive steroid (NS) allopregnanolone, and it has been hypothesized that NS induction may contribute to the therapeutic actions of these agents. Pregnenolone administration improves learning and memory in rodent models, and decreases in this NS have been associated with depressive symptoms in humans. These pregnenolone characteristics may be relevant to the actions of antipsychotics. We therefore investigated potential pregnenolone alterations in rat hippocampus and cerebral cortex following clozapine, olanzapine, and other second generation agents as a candidate NS mechanism contributing to antipsychotic efficacy. In the first set of experiments, intact, adrenalectomized, and sham-operated male rats received vehicle or clozapine (20 mg/kg) IP. In the second set, male rats received vehicle, olanzapine (5 mg/kg), quetiapine (20 mg/kg), ziprasidone (10 mg/kg) or aripiprazole (5 mg/kg) IP. Pregnenolone levels were determined by gas chromatography/mass spectrometry. Clozapine markedly elevates pregnenolone in rat hippocampus, cerebral cortex, and serum; hippocampal levels were strongly correlated with serum levels (r=0.987). Olanzapine also elevates pregnenolone levels, but to a lesser degree than clozapine. Pregnenolone induction may contribute to the clinical actions of clozapine and olanzapine.

Full Text

Duke Authors

Cited Authors

  • Marx, CE; Shampine, LJ; Duncan, GE; VanDoren, MJ; Grobin, AC; Massing, MW; Madison, RD; Bradford, DW; Butterfield, MI; Lieberman, JA; Morrow, AL

Published Date

  • August 2006

Published In

Volume / Issue

  • 84 / 4

Start / End Page

  • 598 - 608

PubMed ID

  • 16962649

International Standard Serial Number (ISSN)

  • 0091-3057

Digital Object Identifier (DOI)

  • 10.1016/j.pbb.2006.07.026

Language

  • eng

Conference Location

  • United States