Biophysical Society Thematic Meeting| Padova 2019

Quantitative Aspects of Membrane Fusion and Fission

Poster Abstracts

61-POS Board 61 DIFFERENTIAL CO-RELEASE OF TWO NEUROTRANSMITTERS FROM A VESICLEFUSION PORE IN MAMMALIAN ADRENAL CHROMAFFIN CELLS Zhuan Zhou 1 ; Qihui Wu 1 ; Bin Liu 1 ; Quanfeng Zhang 1 ; 1 Institute of Molecular Medicine, Peking University, Beijing, China Co-release of multiple neurotransmitters from secretory vesicles is common in neurons and neuroendocrine cells. However, whether and how the transmitters co-released from a single vesicle are differentially regulated remain unknown. In matrix-containing dense-core vesicles (DCVs) in chromaffin cells, there are two modes of catecholamine (CA) release from a single DCV: quantal and sub-quantal. By combining two microelectrodes to simultaneously record co- release of the native CA and ATP from a DCV, we report that (1) CA and ATP were co-released during a DCV fusion; (2) during kiss-and-run (KAR) fusion, the co-released CA was sub- quantal, while the co-released ATP was quantal; (3) knockdown and knockout of the DCV matrix led to quantal co-release of both CA and ATP, even in the KAR mode. These findings strongly imply that, in contrast to the sub-quantal CA release in chromaffin cells, fast synaptic transmission without transmitter-matrix binding is mediated exclusively via quantal release in neurons.

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