mGluR5 Modulation as a Treatment for Parkinson’s Disease

Parkinson's disease is an age related neurodegenerative disease. Current treatments do not reverse the degenerative course; rather they merely manage symptom severity. As such there is an urgent need to develop novel neuroprotective therapeutics. There is an additional need to stimulate and promote inherent neuro-recovery processes. Such processes could maximize the utilization of the existing dopamine neurons, and/or recruit alternate neuronal pathways to promote recovery. This thesis investigates the therapeutic potential of the mGluR5 negative allosteric modulator CTEP in a 6-hydroxydopamine mouse model of Parkinson's disease. We found that CTEP caused a modest reduction in the parkinsonian phenotype after only 1 week of treatment. When administered for 12 weeks, CTEP was able to completely reverse any parkinsonian behaviours and resulted in full dopaminergic striatal terminal re-innervation. Furthermore, restoration of the striatal terminals resulted in normalization of hyperactive neurons in both the striatum and the motor cortex. The beneficial effects within the striatum were associated with an increase activation of mTOR and p70s6K activity. Accordingly, the beneficial effects of CTEP can be blocked if co-administered with the mTOR complex 1 inhibitor, rapamycin. In contrast, CTEP had differential effect in the motor cortex, promoting ERK1/2 and CaMKIIα instead of mTOR. Together these data suggest that modulating mGluR5 with CTEP may have clinical significance in treating Parkinson's disease. In addition to the CTEP work, extensive appendices are included in this thesis outlining the optimization of animal models and tools used in the present thesis, as well as other potential therapeutic avenues.