Title: ~(125)I-IBZM autoradiographic study of striatal dopamine D_2 receptor activity in MPTP-induced mouse model of Parkinson's disease
Abstract:Objective To measure the activity of striatal dopamine D 2 receptor (D 2R) in varying degrees of damage of Parkinsonian mice model by autoradiography with 125 I IBZM, and to evaluate the clinical sign...Objective To measure the activity of striatal dopamine D 2 receptor (D 2R) in varying degrees of damage of Parkinsonian mice model by autoradiography with 125 I IBZM, and to evaluate the clinical significance of the 125 I IBZM imaging for D 2R. Method With regard to the use of MPTP in varying periods, the C57BL mice were randomly divided into the MPTP 1 ,3 ,5 ,7 day groups and saline treated control group. One hour after bolus intravenous injection with 125 I IBZM containing 20 μCi, the brain tissue sections were imaged by autoradiography. The contents of dopamine (DA) and the metabolites were measured by high performance liquid chromatography and electrochemical detection (HPLC ECD). The tyrosine hydroxylase (TH) of immunoreactive cells and fibers in Substantia nigra and the striatum of the mice were observed by immunohistochemical assay. Results The intensity of 125 I IBZM accummulated in striatum of varying degrees of damage of Parkinsonian mice model was compared with that of saline treated control group. The radioactive ratios of striatum/cortex in the MPTP treated groups at 1,3 and 5 days increased by 8%, 16% and 17%, respectively, and no difference was noted in the 7 day MPTP damaged group. The levels of DA in the striatum in varying degrees of MPTP damaged mice were reduced significantly by 47%, 75% 95% and 95%, respectively, as compared with those of control group. One could see the gradual loss of DAergic neurons and fibers in the substantia nigra and striatum of MPTP treated groups. Conclusion Up regulating activity of D 2R was found in the mild damage group, but not in the severe ones. The experiment indicated that the use of DR agonists should be recommended at the earliest stage of PD, and the dynamic imaging study for the status of D 2R in vivo may be helpful to estimate the response to L dopa or DR agonist in different stages of the disease. (Shanghai Med J, 2000,23∶666 669.)Read More
Publication Year: 2000
Publication Date: 2000-01-01
Language: en
Type: article
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