RT Journal Article
SR Electronic
T1 The Effects of Vesicular Volume on Secretion through the Fusion Pore in Exocytotic Release from PC12 Cells
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 303
OP 309
DO 10.1523/JNEUROSCI.1119-03.2004
VO 24
IS 2
A1 L. A. Sombers
A1 H. J. Hanchar
A1 T. L. Colliver
A1 N. Wittenberg
A1 A. Cans
A1 S. Arbault
A1 C. Amatore
A1 A. G. Ewing
YR 2004
UL http://www.jneurosci.org/content/24/2/303.abstract
AB Many spikes in amperometric records of exocytosis events initially exhibit a prespike feature, or foot, which represents a steady-state flux of neurotransmitter through a stable fusion pore spanning both the vesicle and plasma membranes and connecting the vesicle lumen to the extracellular fluid. Here, we present the first evidence indicating that vesicular volume before secretion is strongly correlated with the characteristics of amperometric foot events. l-3,4-Dihydroxyphenylalanine and reserpine have been used to increase and decrease, respectively, the volume of single pheochromocytoma cell vesicles. Amperometry and transmission electron microscopy have been used to determine that as vesicle size is decreased the frequency with which foot events are observed increases, the amount and duration of neurotransmitter released in the foot portion of the event decreases, and vesicles release a greater percentage of their total contents in the foot portion of the event. This previously unidentified correlation provides new insight into how vesicle volume can modulate the activity of the exocytotic fusion pore.