Originally Posted by paula_w

could this be what the infamous neuro gang is referring to when they say freezing, falling and gait dysfunction are nondopaminergic? the second pathway, the indirect pathway? see below from Addex website:

1) mGluR4 activation triggers a compensatory mechanism, mediated by glutamate, that may spare and/or potentiate the use of dopamine receptor activators;
2) mGluR4 activation may have neuroprotective effects that help preserve the brain’s dopaminergic neurons, thus delaying progression of the disease.

Dopamine functions in the brain at the top of the basal ganglia motor circuit, which is composed of two pathways — the “direct” pathway and the “indirect” pathway — that regulate signaling to the thalamus via two brain regions in the basal ganglia system: the substantia nigra pars reticulate (SNr), and the internal globus pallidus (GPi). Both direct and indirect pathways target the thalamus via a non-dopaminergic mechanism (GABA signaling).

The direct and indirect pathways balance each other. The direct pathway exerts an inhibitory effect on SNr/GPi signaling, while the indirect pathway exerts an excitatory effect; both must operate in balance for the thalamus to allow normal motor function.

paula