The Affect of Wellbutrin on Dopamine Reuptake Transporters in
Rodent Striatal Tissue
Jamie L. Doyle, Veronica Chiu, and James O. Schenk
Washington State University, Department of Chemistry, Pullman, WA 99613
Introduction
Rotating Disk
Electrode
Rotator and
Controller
Comparing Reuptake Velocities
2.00E-09
1.80E-09
Reference
Electrode
Potentiostat
1.60E-09
Velocity (mol/g/s)
Neurotransmitter reuptake is an important
process involved in keeping the body functioning
properly, and disruption of reuptake can variably
affect the body and brain. Dopamine (Figure 1), a
neurotransmitter associated with movement and
Parkinson’s disease as well as sensations such as
reward/punishment, sleep, and mood, mediates
feelings of euphoria or depression depending on
the heightened or lowered synaptic concentrations
present, respectively. Drugs such as cocaine or
bupropion (commonly known as Wellbutrin [Figure
2]) will produce an excess of dopamine in the
synapse, by blocking reuptake transporters in the
neuron thereby boosting signaling to post-synaptic
cells. Wellbutrin, often used as an anti-depressant,
supposedly boosts the concentration of dopamine
to an average level in the synaptic gap by inhibiting
the reuptake transporters.
An in vitro study
comparing reuptake velocities, in the presence and
absence of bupropion, was performed in order to
better understand the affects of bupropion on this
transporter. A rotating disk electrode was used to
measure electrochemical changes in rodent striatal
tissue following sequential additions of Wellbutrin
and dopamine. The changes in electrochemical
signal were then converted to reuptake velocities
through a sequence of data manipulations.
95% O2 + 5% CO2
Oscilloscope
Auxiliary
Electrode
Figure 3. A
coronal slice of a
rodent brain,
exposing the
striatum, directly
below the corpus
callosum.
0.25 uM
8.00E-10
0.50 uM
6.00E-10
0.00E+00
Constant Temperature
Circulating Water Bath
0
0.2
0.4
0.6
0.8
1
1.2
Concentration of Dopamine (uM)
Figure 6. The plot of the concentration of dopamine
added versus the calculated reuptake velocities.
Figure 4. The setup of the rotating disk
electrode with tissue in chamber.
A glassy carbon rotating disk electrode (Figure 4)
was then placed into the cell and rotation begun at
2,000 rpm
The electrode was allowed to equilibrated to the
tissue sample (Potentiostat set to 450 mV, and
sample chamber heated to 37ºC with air flow set to
95% O2, 5% CO2 )
Inject dopamine or dopamine/bupropion solutions
and analyze data by correcting the signal with the
baseline
Run regression statistics on concentrations to
solve for initial velocity using the equation:
Output V  iL  [DA]
•Wellbutrin showed an inhibitory affect on the
striatum as hypothesized (Figure 6)
•The reuptake transporter showed the most
inhibition from the 1 μM solution of Wellbutrin as
expected
•The 0.50 μM solution of Wellbutrin showed the
lowest degree of inhibition and actually expressed
catalytic affects when compared to the control
•Compared to the control, the degree of inhibition
provides evidence that non-competitive inhibition
may be ruled out as a possibility (Figure 7)
Concentration vs. % Inhibition
Percent Inhibition (%)
30
Oscilloscope Reading
Figure 2. The structure
of bupropion.
Male Sprague-Dawley rats (300-500g) were
rapidly decapitated and the brain dissected on ice
Striata (Figure 3) were removed and chopped by
hand with a razor blade, and washed eight times in
500 μL of fresh oxygenated buffer
1.00E-09
2.00E-10
Results and Discussion
Methods
Control
1 uM
1.20E-09
4.00E-10
(TotalVolum e)(Slope)
Re uptakeVelo city 
MassofStriatum
Figure 1. The structure of
dopamine.
1.40E-09
20
10
0
-10 0
0.2
0.4
0.6
0.8
1
1.2
-20
-30
0.50 uM Wellbutrin
-40
1.0 uM Wellbutrin
2.5
Concentration of Dopamine (uM)
0.0
Figure 7. A graphical representation of the percent
inhibition for each Wellbutrin concentration. The 0.50 μM
dopamine concentration was omitted due to the presence
of a constant value despite the differing concentrations.
0.25 uM Wellbutrin
-2.5
Future Directions
 Focus research on types of inhibition excluding
non-competitive to better understand the
mechanism of Wellbutrin binding
-5.0
-7.5
0
10
20
30
40
50
60
70
80
90
Time (sec)
Figure 5. A raw data signal which is later
converted to reuptake velocity using initial slope.
Investigate the affects of known Wellbutrin
metabolites, S,S-hydroxybupropion and threohydroxybupropion, on the reuptake transporters in
comparison to the parent drug
This work was supported by the National Science Foundation’s REU program under grant number 0851502