Caspase-3 activation in rat frontal cortex following treatment with typical and atypical antipsychotics

Neuropsychopharmacology. 2007 Jan;32(1):95-102. doi: 10.1038/sj.npp.1301074. Epub 2006 Apr 12.

Abstract

In schizophrenia, studies indicate that apoptotic susceptibility in cortex may be increased. A role for apoptosis in schizophrenia could potentially contribute to post-mortem evidence of reduced cortical neuropil and neuroimaging studies showing progressive cortical gray matter loss. Interestingly, antipsychotic treatment has been associated with higher cortical levels of anti-apoptotic Bcl-2 protein in rat cortex and preliminary data has suggested a similar association in schizophrenia and bipolar disorder. To better understand the effects of antipsychotics on apoptotic regulation, rats were administered haloperidol, clozapine, quetiapine, or saline daily for 4 weeks. Multiple apoptotic markers, including Bcl-2, pro-apoptotic Bax, anti-apoptotic XIAP, and the downstream protease caspase-3 were measured in frontal cortex using Western blot. Caspase-3 activity, activated caspase-3-positive cell number, and DNA/histone fragmentation levels were also determined. Western blot showed that immunoreactivity of Bax and Bcl-2 bands were unchanged with treatment. However, mean density of the 19 kD activated caspase-3 band was 55% higher with haloperidol (p<0.001), 40% higher with clozapine (p<0.05), and 48% higher with quetiapine (p<0.01) compared to saline control. Specific activity of caspase-3 was also increased across all treatments (p<0.0001), while DNA fragmentation rates remained unchanged. These data suggest that sub-chronic antipsychotic treatment is associated with non-lethal caspase-3 activity. The findings do not support a prominent Bcl-2-mediated neuroprotective role for antipsychotics. Although the association between antipsychotic treatment and increased pro-apoptotic caspase-3 is intriguing, further study is needed to understand its potential effects.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Antipsychotic Agents / pharmacology*
  • Blotting, Western / methods
  • Caspase 3 / metabolism*
  • Cell Death / drug effects
  • Enzyme Activation / drug effects
  • Enzyme-Linked Immunosorbent Assay / methods
  • Frontal Lobe / drug effects*
  • Male
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • X-Linked Inhibitor of Apoptosis Protein / metabolism
  • bcl-2-Associated X Protein / metabolism

Substances

  • Antipsychotic Agents
  • Proto-Oncogene Proteins c-bcl-2
  • X-Linked Inhibitor of Apoptosis Protein
  • bcl-2-Associated X Protein
  • Caspase 3