Fig. 4

A C. elegans model of toxin-induced Parkinson’s disease. a Dopaminergic (DA) neuronal cell bodies and neurites in BY250 worms were visualised using an integrated Pdat-1::GFP dopamine transporter marker. C. elegans has eight DA neurons: six are located in the anterior region, which can be subclassified in pairs as two anterior deirid neurons (ADE), two dorsal cephalic neurons (CEP) which are postsynaptic to the ADE neurons and two ventral CEPs that are not postsynaptic to the ADEs; two posterior deirid neurons (PDE) located posteriorly are also shown. Arrows depict the four CEP neuron processes and indicate the ADE and PDE cell bodies in a young worm. Anterior is to the left. b Representative examples of worms scored which display the three characteristic stages of DA neurodegeneration in response to 6-OHDA. Magnification of anterior region of C. elegans shows only the anterior-most DA neurons. WT: in this example, all six anterior DA neurons of this worm appear robust and the dendrites are intact and fully extended. Neuronal process blebbing; cell body rounding: this worm exhibited prominent cell body rounding (asterisk) and dendrite blebbing (arrows); cell body loss: this worm exhibited a complete loss of GFP in most DA neurons as CEP and ADE neurons have all degenerated and are no longer visible in any focal plane, only retention of GFP expression in the remnants of neuron cell bodies and broken neurites. All scale bars represent 20 μm. c Representative images of worms 24 h post-6-OHDA-exposure are presented. BY250 worms treated with ascorbic acid (AA) alone expressed intact and strong GFP in all six DA neurons and dendrites in the heads. However, the majority of BY250 worms incubated with 50 mM 6-OHDA showed a marked GFP expression reduction in the dendrites of ADEs and CEPs, many of the cell somas became round (asterisk) and blebs appeared along the dendrites of CEPs (arrows)