Dopamine Transporter Loss in 6-OHDA Parkinson’s Model Is Unmet by Parallel Reduction in Dopamine Uptake
Figure 5
Dopamine uptake profiles with monoamine competition in 6-OHDA-lesioned striatum versus intact striatum. A.
Dopamine. 1 µM DA was added in striatal synaptosomes prepared from at least 70% lesioned striatum and from the operationally-matched contralateral control. After 5 min preincubation period, 500 nM [7-, 8- 3H-DA] was added and uptake was determined for 2 min. In the lesioned striatal synaptosomes, DA was significantly less effective (30% less inhibition than in control) effective to inhibit DA uptake, as compared to the control. Statistics: *p<0.05, t = 3.47, two-tailed Student’s paired t-test, n = 6 paired observations. B. Norepinephrine 1 µM NE was added in striatal synaptosomes prepared from at least 70% lesioned striatum and from the operationally-matched contralateral control. After 5 min preincubation period, 500 nM [7-, 8- 3H-DA] was added and uptake was determined for 2 min. In the lesioned striatal synaptosomes, NE was significantly more effective (38% greater inhibition than in control) to inhibit DA uptake, as compared to the control. Statistics: *p<0.05, t = 2.59, two-tailed Student’s paired t-test, n = 6 paired observations. C. Serotonin 1 µM 5-HT was added in striatal synaptosomes prepared from at least 70% lesioned striatum and from the operationally-matched contralateral control. After 5 min preincubation period, 500 nM [7-, 8- 3H-DA] was added and uptake was determined for 2 min. There was no significant difference in the ability of 5-HT to inhibit DA uptake in lesioned striatal synaptosomes, as compared to the control, n = 6 paired observations.