Excitotoxicity induces activation of caspase 3 which is prevented by microtubule stabilization. a. Active caspase-3 immunoreactivity was low in control (vehicle) treated chambers but was present in many axons as discrete puncta following kainic acid. Caspase immunoreactivity was not altered at 1 hour following kainic acid exposure but was significantly increased at 16 hrs. b,c. Kainic acid induced active caspase-3 immunoreactivity in the axon compartment was significantly attenuated by either somatodendritic or axonal taxol treatment. KA, kainic acid. * Significantly different from control. # Significantly different from kainic acid treatment. P < 0.05. Mean values shown ± SEM. Scale bar: 20 μm.