%0 Journal Article
%T Dopamine Receptors and Parkinson's Disease
%A Shin Hisahara
%A Shun Shimohama
%J International Journal of Medicinal Chemistry
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/403039
%X Parkinson's disease (PD) is a progressive extrapyramidal motor disorder. Pathologically, this disease is characterized by the selective dopaminergic (DAergic) neuronal degeneration in the substantia nigra. Correcting the DA deficiency in PD with levodopa (L-dopa) significantly attenuates the motor symptoms; however, its effectiveness often declines, and L-dopa-related adverse effects emerge after long-term treatment. Nowadays, DA receptor agonists are useful medication even regarded as first choice to delay the starting of L-dopa therapy. In advanced stage of PD, they are also used as adjunct therapy together with L-dopa. DA receptor agonists act by stimulation of presynaptic and postsynaptic DA receptors. Despite the usefulness, they could be causative drugs for valvulopathy and nonmotor complication such as DA dysregulation syndrome (DDS). In this paper, physiological characteristics of DA receptor familyare discussed. We also discuss the validity, benefits, and specific adverse effects of pharmaceutical DA receptor agonist. 1. Introduction Parkinson¡¯s disease (PD) is a common progressive neurodegenerative disorder that can be accurately diagnosed. A recent meta-analysis study indicated that standardized all-age prevalence of 51.3 to 176.9 per 100£¿000 in door-to-door surveys and prevalence in record-based studies ranged from 35.8 to 68.3 per 100£¿000 in Asia [1]. The standardized incidence rates were 8.7 per 100£¿000 person-years in door-to-door surveys and 6.7 to 8.3 per 100£¿000 person-years in record-based surveys [1]. Clinical symptoms in PD comprise both motor and nonmotor symptoms. PD patients show slowness of initiation of voluntary movements with progressive reduction in speech (bradykinesia), muscular rigidity, resting tremor, and postural instability. Additionally, it is known that almost 90% of PD patients experience nonmotor symptoms during the course of disease [2]. The spectrum of nonmotor symptoms is also very broad and comprises neuropsychiatric conditions, such as depression, dementia, and hallucinations as well as autonomic, sensory, and REM sleep behavior disorders. A region-specific selective loss of dopaminergic (DAergic) neuromelanin-containing neurons from the pars compacta of the substantia nigra (SNpc) is the pathological hallmark of PD. However, cell loss in the locuscoeruleus, dorsal nuclei of the vagus, raphe nuclei, nucleusbasalis of Meynert, and some other catecholaminergic brain stem structures including the ventrotegmental area also exists [3]. This neuronal cell loss is accompanied by intraneuronal inclusions: the Lewy
%U http://www.hindawi.com/journals/ijmc/2011/403039/