Neurotransmitter current not flowing through ion channels
(NC&T/CU) These results were reported July 22 in the online
edition of the journal Nature Cell Biology by Cornell
researchers Liang-Wei Gong and Manfred Lindau, applied and
engineering physics, as well as their colleague Guillermo
Alvarez de Toledo at the University of Seville, Spain. Lindau
explained that neurotransmitters and hormones are stored in
neurons -- nerve cells -- in small packets, membrane-bound
vesicles, typically 30 to 300 nanometers in diameter (a
nanometer is one-billionth of a meter). When a cell is
stimulated by electrical activity, calcium ions enter the cell
and the vesicles release their contents by fusion with the
plasma membrane surrounding the cell. Prior experiments had
suggested that the vesicles contain ion channels that carry
charged neurotransmitters from the cell vesicle out of the cell,
generating an electrical current flowing out of the cell. Lindau
and colleagues report in their paper that there is no such
current pres