Increased expression of dopamine receptors on lymphocytes in Parkinson's disease

Abstract

Dopamine D1‐like and D2‐like receptors on peripheral blood lymphocytes (PBL) were assayed in 50 de novo patients with idiopathic Parkinson's disease (PD), in 36 neurologic control subjects (multiple‐system atrophy, n = 16; essential tremor, n = 10; other neurodegenerative diseases, n = 10), and in 26 healthy control subjects by radioligand binding assay techniques using [3H]SCH 23390 and [3H]7OH‐DPAT as ligands. Patients with PD revealed a higher density (Bmax) of dopamine D1‐like (p <0.001) and D2‐like (p <0.00001) receptors on PBL than either neurologic or healthy control subjects, whereas no differences in Bmax were observed among patients affected by other neurologic diseases and healthy control subjects. The affinity (Kd) of both radioligands was similar in the groups investigated. The pharmacologic profile of [3H]SCH 23390 and [3H]7OH‐DPAT binding was consistent with the labeling of dopamine D5 and D3 receptor subtypes, respectively. Twenty‐five of the 50 patients with PD were retested after 3 months of therapy with levodopa or bromocriptine. Both treatments reduced the density of D1‐like (p <0.001) and D2‐like (p <0.001) receptors on PBL to values comparable to those of control subjects. The increased density of D1‐like and D2‐like receptors on PBL in de novo PD patients may represent an upregulation mechanism resulting from the diffuse impairment of the dopaminergic system in PD.

Dopamine D1-Like Receptor Antagonist Attenuates Th17-Mediated Immune Response and Ovalbumin Antigen-Induced Neutrophilic Airway Inflammation

“…The extent of dopamine receptor expression is different among diseases (51)(52)(53)(54)(55). For example, expression of D3 receptor is upregulated in schizophrenia (51,52).…”

“…Expression of D2-like-R decreased in Alzheimer's disease (53). Furthermore, Barbanti et al (54) reported that expression of D1-like-R and D2-like-R on PBLs was upregulated in Parkinson's disease. However, the expression of dopamine receptor in asthma and the effect of asthma severity on the expression of dopamine receptor were not investigated.…”

Biomarkers for Evaluation of Clinical Efficacy of Multipotential Neuroprotective Drugs for Alzheimer's and Parkinson's Diseases

“…Subsequently, additional studies performed on lymphocytes or platelets of PD patients have detected subtle abnormalities in DA signaling [66][67][68] or mitochondrial functions, 69 -72 which con-…”

Identification of Splice Variants as Molecular Markers in Parkinson's Disease

“…Peripheral lymphocytes are genetically determined and contain most if not all the same molecules implicated in PD pathogenesis including DA, DA receptors, α-synuclein, parkin, mitochondria, glutathione and glutathione-related enzymes as well as proteasomes (Yoshino et al, 1992;Barroso et al, 1993;Sunada et al, 1998;Barbanti et al, 1999;Caronti et al, 1999;Shin et al, 2000). There is limited evidence to suggest that some of these molecules are different in the peripheral blood lymphocytes of PD patients compared to controls.…”