D2 receptor antagonist raclopride regulates glutamatergic neuronal activity in the pedunculopontine nucleus in a rat model of Parkinson's disease

Parkinson disease (PD) is defined by the loss of dopamine (DA). Changes in the pedunculopontine nucleus (PPN), particularly in local field potential (LFP), can be attributed to deficits in DA and DA receptor expression levels. PPN is a heterogeneous nucleus consisting of cholinergic, γ-aminobutyric acid (GABAergic), and glutamatergic neurons. However, it is unclear whether low levels of DA receptors affect the activity of different PPN neuron types. We record the neuronal activity of PPN by administering the selective dopamine D1 and D2 receptor antagonists, SCH23390 and Raclopride, respectively. This study discover that the firing rates of glutamatergic neurons could be normalized, and their firing patterns were more consistent in lesioned rats treated with raclopride. Raclopride administration could correct the increased coherence and phase locking between glutamatergic spikes and beta-band oscillatory activity in lesioned rats. Raclopride administration correct the increased coherence and phase locking between glutamatergic spikes and beta-band oscillatory activity in lesioned rats.