Fig. 4.

A–F, Neuroprotection: ablation of the inferior olive with 3-AP prevents or greatly attenuates Purkinje cell degeneration induced by ibogaine. Left column(A, C, E), Treatment with ibogaine alone produces radial bands of Purkinje cell loss manifested by pale, unstained gaps in the molecular and Purkinje cell layers. Loss of Purkinje cells is most prominent in the vermis but is also present in the paravermis and simplex lobule. Right column (B, D, F), Animals that received the 3-AP regimen followed by ibogaine 6 d later demonstrate marked neuroprotection against Purkinje cell degeneration. The nearly continuous immunostaining of Purkinje cell bodies and of their dendrites in the molecular layer (B, D, F) indicates that there is little or no ibogaine-induced degeneration of Purkinje cells after olive ablation. Infrequently in rats that received the 3-AP regimen plus ibogaine, a single Purkinje cell may have degenerated (see thin gapin neuronal staining of molecular and Purkinje cell layers inupper right corner of D). Photomicrographs show Purkinje cells in coronal sections immunostained with antiserum to Cam-kin II. Ibogaine dose, 100 mg/kg once; in all cases, survival was 7 d after ibogaine administration. Scale bars:A, B, 500 μm; C–F, 100 μm.