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Elementary properties of spontaneous fusion of peptidergic vesicles: fusion pore gating
Author(s) -
Vardjan Nina,
Stenovec Matjaž,
Jorgačevski Jernej,
Kreft Marko,
Zorec Robert
Publication year - 2007
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2007.136135
Subject(s) - fusion , gating , vesicle , biophysics , chemistry , neuroscience , biology , biochemistry , membrane , philosophy , linguistics
The release of hormones and neurotransmitters by regulated exocytosis requires the delivery of secretory vesicles to the plasma membrane, where they dock and become primed for fusion with the plasma membrane. Upon stimulation a fusion pore is formed through which cargo molecules diffuse out of the vesicle lumen into the extracellular space. After the cargo release the fusion pore either closes (kiss‐and‐run, transient exocytosis), fluctuates between an open and a closed state (for short times, fusion pore flickering, or for rather longer periods, ‘pulsing pore’) or expands irreversibly (full fusion exocytosis). In almost all secretory cells spontaneous secretion of vesicle cargo can be detected in the absence of stimulation. Spontaneous and stimulated exocytosis were thought to exhibit similar properties at elementary level, differing only in the probability of occurrence. However, recent studies indicate that spontaneous exocytosis differs from the stimulated one in many respects, therefore opening questions about the physiological role of spontaneous exocytosis. In this report we address the elementary properties of spontaneous and stimulated peptidergic vesicle discharge which appears to be modulated by fusion pore conductance (diameter) and fusion pore gating.