Alteration in L-DOPA evoked dopamine and DOPAC output under conditions of impaired vesicular dopamine storage.

Title

Alteration in L-DOPA evoked dopamine and DOPAC output under conditions of impaired vesicular dopamine storage.

Creator

Xu K; Dluzen D E

Publisher

Journal of neural transmission (Vienna, Austria : 1996)

Date

1998
1905-06

Description

We examined the effect of L-dihydroxyphenylalanine (L-DOPA) infusion in vitro upon dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) output from superfused corpus striatum of vehicle and reserpine or tetrabenazine (TBZ) treated male rats. Specifically, we tested the effects of two 20-min infusions of L-DOPA (5 uM) upon DA and DOPAC output (pg/mg/min) in reserpine (5 mg/kg, i.p., 24 hours before sacrifice; n=11), TBZ (30 mg/kg, i.p. 1 hour before sacrifice; n=8) or vehicle (n=21) treated rats. There was an overall significantly higher L-DOPA evoked DA output from the vehicle (12.22+/-1.74) versus reserpine (4.39+/-2.40) (p \textless 0.05), but not TBZ (9.16+/-2.81) treated rats. In addition, the DA response to the second L-DOPA infusion was significantly increased over that of the first response in the vehicle (9.40+/-2.11 vs. 15.04+/-2.78) (p \textless 0.05), but not reserpine or TBZ treated rats. The overall DOPAC outputs did not achieve a statistically significant difference among all treatment groups. However, the DOPAC outputs following the second L-DOPA infusion were significantly reduced in reserpine (41.15+/-6.10 vs. 20.27+/-4.54) and TBZ (21.38+/-4.41 vs. 10.87+/-2.36) (both p \textless 0.05), but not vehicle (28.99+/-4.00 vs. 24.91+/-4.78) treated rats. We conclude that: 1) the storage capacity of DA neurons is one of the important elements involved in affecting L-DOPA's effects upon DA and DOPAC output, 2) the shunting of storage to metabolism may represent a common characteristic in impaired nigrostriatal dopaminergic system, and 3) TBZ may operate differently from reserpine in the nigrostriatal dopaminergic system.

Subject

3; 4-Dihydroxyphenylacetic Acid/*metabolism; Animals; Dopamine Agents/*pharmacology; Dopamine/*metabolism; Levodopa/*pharmacology; Male; Pharmaceutical Vehicles; Rats; Reserpine/pharmacology; Sprague-Dawley; Synaptic Vesicles/*drug effects/metabolism; Tetrabenazine/pharmacology

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

1091–1101

Issue

10

Volume

105

Citation

Xu K; Dluzen D E, “Alteration in L-DOPA evoked dopamine and DOPAC output under conditions of impaired vesicular dopamine storage.,” NEOMED Bibliography Database, accessed April 15, 2021, https://neomed.omeka.net/items/show/3204.

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