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

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-<i>Cckar</i> and <i>Glp1r</i> were undetectable. In intact mice, the expression of <i>Drd2</i>, <i>Grin2b</i>, <i>Grm1</i> and <i>Ntsr2</i> predominates in SNpc tissue, whereas that of <i>Gria2</i>, <i>Chrnb2</i>, <i>Gper1</i>, <i>Igf1r</i> 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, <i>Drd2</i> expression increased and <i>Gria2</i> decreased, whereas in a clinical model, <i>Drd2</i>, <i>Grm1</i>, <i>Ntsr2</i> 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.