# Expression of Genes Encoding Receptors for Classical Neurotransmitters, Neuropeptides and Hormones in the Substantia Nigra, Especially in Dopaminergic Neurons, in Intact Mice and Mouse Models of Parkinson’s Disease

## TL;DR

This study explores gene expression in brain cells affected by Parkinson’s disease, identifying potential targets for new treatments.

## Contribution

The study identifies specific receptor genes expressed in dopaminergic neurons and their altered expression in Parkinson’s disease models.

## Key findings

- 12 receptor-encoding genes are expressed in the substantia nigra, but only 10 in isolated dopaminergic neurons.
- Gene expression in dopaminergic neurons changes in Parkinson’s disease models, especially Drd2 and Gria2.
- Altered receptor gene expression in Parkinson’s models suggests potential for receptor-targeted therapies.

## Abstract

Parkinson’s disease (PD) is characterized by degeneration of nigrostriatal dopaminergic neurons (DNs) and movement disorders. Low efficiency of pharmacotherapy requires improvement, e.g., using receptor agonists or antagonists as drugs. Our work aims to initiate these developments by studying the expression levels of genes encoding neurotransmitters, neuropeptides and hormone receptors in substantia nigra pars compacta (SNpc) cells and in isolated DNs in intact mice, and changes in expression of these genes in MPTP mouse models of PD at preclinical and clinical stages. Expression of all 12 studied genes was detected in the SNpc and only 10 in DNs—Cckar and Glp1r were undetectable. In intact mice, the expression of Drd2, Grin2b, Grm1 and Ntsr2 predominates in SNpc tissue, whereas that of Gria2, Chrnb2, Gper1, Igf1r is higher in DNs. In PD models, change in receptor gene expression was detected in DNs but not in SNpc tissue. In the preclinical PD, Drd2 expression increased and Gria2 decreased, whereas in a clinical model, Drd2, Grm1, Ntsr2 expression decreased. Thus, the above genes are expressed in DNs and other cells of SNpc; expression of some genes changes in PD models, which opens up prospects for development of therapy using receptor agonists and antagonists.