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Spontaneous and action potential-evoked Ca2+ release from endoplasmic reticulum in neocortical synaptic boutons
Spontaneous and action potential-evoked Ca2+ release from endoplasmic reticulum in neocortical synaptic boutons
- Source :
- Cell Calcium. 97:102433
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Although the endoplasmic reticulum (ER) is present throughout axons, and IP3 and ryanodine receptors are widely expressed in nerve terminals, whether Ca2+ release from presynaptic stores contributes to action potential (AP)-evoked Ca2+ transients remains controversial. We investigated the release of Ca2+ from ER stores in boutons en passant of neocortical layer 5 pyramidal neurons. A hallmark of these stores is that they spontaneously release Ca2+ at a low frequency. Using a high-affinity Ca2+ indicator, we documented and characterised such spontaneous Ca2+ transients (sCaTs), which occurred at a rate of ~0.2 per min and raised the intracellular Ca2+ concentration ([Ca2+]i) by ~2 µM in the absence of exogenous buffers. Caffeine increased the average frequency of sCaTs by 90%, without affecting their amplitude and decay kinetics. Therefore, presynaptic ryanodine receptors were likely involved. To determine if presynaptic ER stores contribute to intracellular Ca2+ accumulation during repetitive stimulation, we measured [Ca2+]i during 2 s long trains of APs evoked at 10-50 Hz. We found that for frequencies
- Subjects :
- 0301 basic medicine
Physiology
Chemistry
Ryanodine receptor
Endoplasmic reticulum
En passant
Stimulation
Cell Biology
03 medical and health sciences
chemistry.chemical_compound
030104 developmental biology
0302 clinical medicine
Biophysics
Steady state (chemistry)
Ca2 release
Caffeine
Molecular Biology
030217 neurology & neurosurgery
Intracellular
Subjects
Details
- ISSN :
- 01434160
- Volume :
- 97
- Database :
- OpenAIRE
- Journal :
- Cell Calcium
- Accession number :
- edsair.doi...........5da61e93bd24e69837e752e0b05a16b8
- Full Text :
- https://doi.org/10.1016/j.ceca.2021.102433