first column, a single PC12 cell was repeatedly stimulated with 80 mM KCl for 3 s at the arrows; amperometric spikes were elicited in each case. In the second column, a different cell was treated identically except that at 2 min following the first stimulation, 1 µM reserpine was added to the medium. Subsequent stimulations indicate that quantal release is abolished by reserpine. All data were obtained using a 5 µm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from Anal. Chem. with permission [13].)

doi:10.1201/9780203908907-145

Chapter

first column, a single PC12 cell was repeatedly stimulated with 80 mM KCl for 3 s at the arrows; amperometric spikes were elicited in each case. In the second column, a different cell was treated identically except that at 2 min following the first stimulation, 1 µM reserpine was added to the medium. Subsequent stimulations indicate that quantal release is abolished by reserpine. All data were obtained using a 5 µm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from Anal. Chem. with permission [13].)

Chapter

first column, a single PC12 cell was repeatedly stimulated with 80 mM KCl for 3 s at the arrows; amperometric spikes were elicited in each case. In the second column, a different cell was treated identically except that at 2 min following the first stimulation, 1 µM reserpine was added to the medium. Subsequent stimulations indicate that quantal release is abolished by reserpine. All data were obtained using a 5 µm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from Anal. Chem. with permission [13].)

ABSTRACT

In order to further examine this possibility, amperometry and transmission electron microscopy (TEM) have been used simultaneously to directly determine if the L-DOPA and reserpine-mediated effects on quantal release are accompanied by changes in vesicular volume [57]. Pharmacological manipulations utilizing L-DOPA and reserpine directly affect the VMAT-mediated transport of catecholamines into PC12 vesicles [57]. Electron microscopy has been used to measure changes in the size of vesicles not actively involved in exocytosis, and these measurements can be correlated with the amount of neurotransmitter released using amperometry.