Assessments in Primary Parkinson Syndrome for comparison between Mono-dopaminergic and Multi-target Anti-parkinsonian Pharmacotherapies

In this review, the altered functions of neurotransmitters and neuropeptides in the extrapyramidal system in primary Parkinson syndrome are pointed out. In this syndrome, an altered neurotransmitter balance in the nuclei of the extrapyramidal system with hypoactivity of the dopaminergic and GABAergic neurotransmitter systems and hypoactivity of the muscarinic cholinergic and glutamatergic neurotransmitter systems occurs. Serotonin counteracts dopamine deficiency in the putamen via 5-HT2A receptors. Neuropeptides have a modulating function and influence the mentioned neurotransmitter systems. Neurotensin antagonists, at NTS1 receptors, and antagonists, at the mu opioid receptor, could have a therapeutic function in the anti-Parkinsonian pharmacotherapy. A scheme including the possible neural combinations in the neuronal system and considering the mentioned alterations of the neuroactive substances is described. A scientific problem to be investigated is, whether a multi-target pharmacological treatment, i.e. add-on drugs such as agonists of the ß2 nicotinic cholinergic receptor, A2A adenosine antagonists, 5 metabotropic glutamatergic receptor antagonists and/or NTS1 receptor antagonists could exert a neuroprotective effect on dopaminergic neurons and may be slow down the progression of the disease. In clinical studies with Parkinsonian patients, a main goal must be to compare a cohort of Parkinsonian patients receiving a mono-dopaminergic pharmacotherapy with patients receiving multi-target anti-Parkinsonian pharmacotherapy. The motor and cognitive functions could be assessed by assessment tools, and imaging examination techniques should be applied in order to assess the generally progressive course of the illness.