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Figure 5 | BMC Neuroscience

Figure 5

From: Dopamine presynaptically and heterogeneously modulates nucleus accumbens medium-spiny neuron GABA synapses in vitro

Figure 5

Imaging presynaptic modulation by FM1-43 destaining. Synaptic vesicles were loaded (stained) with FM1-43 by field stimulation, and then imaged every 1.25 sec. After a control period (15 images), showing that there was limited bleaching, field stimulation was applied at 4 Hz; destaining was monitored at 8varicosities (thin traces). A. During this stimulation, the D1 agonist SKF38393 (SKF,10 μM) was perfused (10 images). For 5 varicosities (blue traces), there was no inflection in the destaining curve, while in the others (red traces), the destaining was arrested, creating an inflection. The two thick traces are averages of the sets of effect and no-effect traces. The effect traces were offset upwards for the sake of the illustration. Once the SKF38393 was washed off, and the stimulation continued, destaining continued or resumed. After an interval of no stimulation, the remaining FM1-43 was unloaded with a 20 Hz tetanus. A total of 70 images were acquired. B. In another culture, the D2 agonist Quinpirole (Quin, 1 μM) was applied. In this experiment all 8 varicosities showed inhibition (red traces). D2 effects typically had a greater latency; note that the plateau started roughly when the drug was washed off (presumably coincidental). C. Overall, the majority of experiments showed either D1 or D2 inhibition, and in those experiments about half of varicosities showed inhibition (expressed as mean ± s.e.m.). Facilitation, as would be reflected in an increase in the destaining rate, was not seen. In each of the 13 D1 agonist experiments, a minimum of 2 varicosities showed inhibition; in the 18 D2 agonist experiments, 3 experiments had only one varicosity that showed inhibition. In one D1 agonist experiment and in one D2 agonist experiment every varicosity showed inhibition.

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