Several neuropeptides involved in parkinsonian neuroprotection modulate the firing properties of nigral dopaminergic neurons

Parkinson's disease is characterized by progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta. The surviving nigral dopaminergic neurons display altered spontaneous firing activity in Parkinson's disease. The firing rate of nigral dopaminergic neurons decreases long before complete neuronal death and the appearance of parkinsonian symptoms. A mild stimulation could rescue dopaminergic neurons from death and in turn play neuroprotective effects. Several neuropeptides, including cholecystokinin (CCK), ghrelin, neurotensin, orexin, tachykinins and apelin, within the substantia nigra pars compacta play important roles in the modulation of spontaneous firing activity of dopaminergic neurons and therefore involve motor control and motor disorders. Here, we review neuropeptide-induced modulation of the firing properties of nigral dopaminergic neurons. This review may provide a background to guide further investigations into the involvement of neuropeptides in movement control by modulating firing activity of nigral dopaminergic neurons in Parkinson's disease.

Automated summary

Parkinson's disease is characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta, leading to altered firing activity. The firing rate of nigral dopaminergic neurons decreases before complete neuronal death and symptomatic onset. Neuropeptides, such as CCK, ghrelin, neurotensin, orexin, tachykinins, and apelin, play important roles in modulating the firing activity of dopaminergic neurons, impacting motor control and disorders. This review provides insights into the involvement of neuropeptides in Parkinson's disease and may guide further investigations.