title: Caspase-3 activation in rat frontal cortex following treatment with typical and atypical antipsychotics.
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.
authors.affiliation: Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7160, USA. jarskog@med.unc.edu
authors.forename: L Fredrik
authors.initials: LF
authors.lastname: Jarskog
authors.forename: John H
authors.initials: JH
authors.lastname: Gilmore
authors.forename: Leisa A
authors.initials: LA
authors.lastname: Glantz
authors.forename: Karissa L
authors.initials: KL
authors.lastname: Gable
authors.forename: Thomas T
authors.initials: TT
authors.lastname: German
authors.forename: Ruth I
authors.initials: RI
authors.lastname: Tong
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Lieberman
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D015153:Blotting, Western / Q000379:methods; D053148:Caspase 3 / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005625:Frontal Lobe / Q000187:drug effects*; D008297:Male; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D014150:Antipsychotic Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D051636:X-Linked Inhibitor of Apoptosis Protein; D051028:bcl-2-Associated X Protein; D053148:Caspase 3