Abstract
During long-term treatment with Levodopa, majority of patients with Parkinson's disease experience some abnormal motor problems including of Levodopa induced dyskinesia (LID) and wearing off. Incredible evidences suggest that serotonergic neurons compensate some functions of lost dopaminergic neurons in Parkinson's disease especially in advanced disease stages. Therefore, it has been postulated that serotonergic neurons are the major source for development of these unwanted effects. 5HT1A receptors are located on the serotonergic neurons and are involved in regulation of normal motor functions. With respect to the role of serotonergic projection in Parkinson's disease and importance of 5HT1A receptors in motor activity it seems that inactivation of these neurons by stimulation of 5HT1A receptors could provide benefits in treatment of Levodopa induced motor impairments.