title: The role of caspase-3 activation in phencyclidine-induced neuronal death in postnatal rats.
abstract: This study determined the role of caspase-3 in phencyclidine (PCP)-induced neurodegeneration in postnatal rats. PCP administration to postnatal day 7 rats induced a dose-dependent increase in caspase-3 enzymatic activity in frontal cortex, striatum, and hippocampus. Enzymatic activation was present at 4 h, peaked between 6 and 12 h, and disappeared by 24 h. Further, cleaved caspase-3-immunoreactive neurons were detected as early as 2 h in the cortex, and were found throughout the brain, including, in addition, the thalamus and striatum. Within the cingulate, frontal, parietal, and retrosplenial cortices, immunoreactivity was specific for layers II-IV (especially layer II). Neurons positive for both silver staining and terminal deoxynucleotidyl transferase biotin-d-UTP nick-end labeling (TUNEL) were found in the same brain regions and subregions. Double labeling experiments confirmed that cleaved caspase-3 and TUNEL were coexpressed in many neurons in all brain regions and subregions studied. Temporal studies revealed that procaspase-3 cleavage preceded TUNEL staining by about 3 h, with many neurons being positive for both caspase-3 and TUNEL 9 h after PCP treatment. In organotypic corticostriatal slices, PCP caused a concentration- and time-dependent cleavage of procaspase-3 that was also colocalized with TUNEL staining in layers II-IV of the parietal cortex. Caspase-3 activation again preceded PCP-induced DNA damage assessed by TUNEL. PCP-induced neuronal death in vitro as measured by TUNEL staining was blocked 85% by Ac-AAVALLPAVLLALLAPDEVD-CHO, a cell-permeable selective caspase-3 inhibitor. These data demonstrate that caspase-3 activation plays a necessary role in the regionally selective neuronal death induced by PCP in the developing rat brain.
authors.affiliation: Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555-1031, USA.
authors.forename: Cheng Z
authors.initials: CZ
authors.lastname: Wang
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Johnson
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D001921:Brain / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology; D053148:Caspase 3 / Q000187:drug effects / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects / Q000502:physiology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000633:toxicity; D005260:Female; D020287:In Situ Nick-End Labeling; D008297:Male; D009410:Nerve Degeneration / Q000139:chemically induced / Q000201:enzymology* / Q000503:physiopathology; D009924:Organ Culture Techniques; D010622:Phencyclidine / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012559:Schizophrenia / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D053148:Caspase 3; D010622:Phencyclidine