![sizes by percentage. L-DOPA exposure shifts the distribution of quantal sizes to the right. The lower limit of each bin size is displayed on the abscissa. Data sets are not significantly different from normal distribution (Kolmogorov-Smirnov normality test; p>0.05). All data were obtained using a 5 µm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from J. Neurochem. with permission [16].)](https://images.tandf.co.uk/common/jackets/crclarge/978082470/9780824707316.jpg "sizes by percentage. L-DOPA exposure shifts the distribution of quantal sizes to the right. The lower limit of each bin size is displayed on the abscissa. Data sets are not significantly different from normal distribution (Kolmogorov-Smirnov normality test; p>0.05). All data were obtained using a 5 µm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from J. Neurochem. with permission [16].)")
ABSTRACT
Thus, it is clear that the quantal size of a vesicle depends on the extracellular conditions. Pharmacological manipulations of PC12 cells with L-DOPA and amphetamine have both been shown to increase dopamine release; however, these two chemicals work in different ways. L-DOPA acts to increase catecholamine content in the vesicles by increasing cytosolic dopamine synthesis, whereas amphetamine acts to increase dopamine content in the cytosol by depleting it from the vesicles. These results are highly significant, as they define a mechanism for neuroplasticity whereby the amount of messenger released is modulated under different cellular conditions.
