Fig. 4. Caspase-3 activation occurred primarily in neurons. Double staining with antibodies to cleaved caspase-3 (red ) and antibodies to NeuN, a neuron-specific nuclear protein (green ), demonstrated that most of the cleaved caspase-3 positive cells were neurons (scale bar = 100 μm). CFA = complete Freund's adjuvant; KET = ketamine.