Format

Send to

Choose Destination
Biophys J. 2004 Jan;86(1 Pt 1):163-81.

Peripheral hot spots for local Ca2+ release after single action potentials in sympathetic ganglion neurons.

Author information

1
Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA.

Abstract

Ca2+ release from the endoplasmic reticulum (ER) contributes to Ca2+ transients in frog sympathetic ganglion neurons. Here we use video-rate confocal fluo-4 fluorescence imaging to show that single action potentials reproducibly trigger rapidly rising Ca2+ transients at 1-3 local hot spots within the peripheral ER-rich layer in intact neurons in fresh ganglia and in the majority (74%) of cultured neurons. Hot spots were located near the nucleus or the axon hillock region. Other regions exhibited either slower and smaller signals or no response. Ca2+ signals spread into the cell at constant velocity across the ER in nonnuclear regions, indicating active propagation, but spread with a (time)1/2 dependence within the nucleus, consistent with diffusion. 26% of cultured cells exhibited uniform Ca2+ signals around the periphery, but hot spots were produced by loading the cytosol with EGTA or by bathing such cells in low-Ca2+ Ringer's solution. Peripheral hot spots for Ca2+ release within the perinuclear and axon hillock regions provide a mechanism for preferential initiation of nuclear and axonal Ca2+ signals by single action potentials in sympathetic ganglion neurons.

PMID:
14695260
PMCID:
PMC1303780
DOI:
10.1016/S0006-3495(04)74094-1
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center