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Action potential modulates Ca2+-dependent and Ca2+-independent secretion in a sensory neuron.
- Source :
-
Biophysical journal [Biophys J] 2009 Mar 18; Vol. 96 (6), pp. 2449-56. - Publication Year :
- 2009
-
Abstract
- Neurotransmitter release normally requires calcium triggering. However, the somata of dorsal root ganglion (DRG) neurons possess a calcium-independent but voltage-dependent secretion (CIVDS) in addition to the classic calcium-dependent secretion (CDS). Here, we investigated the physiological role of CIVDS and the contributions of CIVDS and CDS induced by action potentials (APs) in DRG soma. Using membrane capacitance measurements, caged calcium photolysis, and membrane capacitance kinetics analysis, we demonstrated that AP-induced secretion had both CIVDS and CDS components. Following physiological stimuli, the dominant component of AP-induced secretion was either CIVDS for spontaneous firing or CDS for high-intensity stimuli. AP frequency modulates CDS-coupled exocytosis and CIVDS-coupled endocytosis but not CIVDS-coupled exocytosis and CDS-coupled endocytosis. Finally, CIVDS did not contribute to excitatory postsynaptic currents induced by APs in DRG presynaptic terminals in the spinal cord. Thus, CIVDS is probably an essential physiological component of AP-induced secretion in the soma. These findings bring novel insights into primary sensory processes in DRG neurons.
- Subjects :
- Animals
Cell Membrane physiology
Cells, Cultured
Electric Capacitance
Endocytosis
Excitatory Postsynaptic Potentials
In Vitro Techniques
Kinetics
Patch-Clamp Techniques
Photolysis
Rats
Rats, Wistar
Action Potentials
Calcium metabolism
Ganglia, Spinal physiology
Neurotransmitter Agents metabolism
Sensory Receptor Cells metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1542-0086
- Volume :
- 96
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Biophysical journal
- Publication Type :
- Academic Journal
- Accession number :
- 19289069
- Full Text :
- https://doi.org/10.1016/j.bpj.2008.11.037