Role of Intracellular Na + in the Regulation of [Ca 2+ ] i in the Rat Suprachiasmatic Nucleus Neurons

Transmembrane Ca influx is essential to the proper functioning of the central clock in the suprachiasmatic nucleus (SCN). In the rat SCN neurons, the clearance of somatic Ca following depolarization-induced Ca transients involves Ca extrusion via Na /Ca exchanger (NCX) and mitochondrial Ca buffering...

Full description

Saved in:
Bibliographic Details
Published in:International journal of molecular sciences 2019-09, Vol.20 (19), p.4868
Main Authors: Cheng, Ruo-Ciao, Cheng, Pi-Cheng, Wang, Yi-Chi, Huang, Rong-Chi
Format: Article
Language:English
Subjects:
Animals
ca2
Calcium (intracellular)
Calcium (mitochondrial)
Calcium - metabolism
Calcium buffering
Calcium channels
Calcium imaging
Calcium influx
Calcium ions
Decay rate
Depolarization
Experiments
Extrusion
Homeostasis
Intracellular
Mitochondria
Mitochondria - metabolism
Monensin
na+
Na+/Ca2+ exchanger
na+/k+-atpase
Na+/K+-exchanging ATPase
Neurons
Nimodipine
Nimodipine - pharmacology
Ouabain
Rats
Sodium - metabolism
Sodium-Calcium Exchanger - metabolism
Suprachiasmatic nucleus
Suprachiasmatic Nucleus Neurons - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Transmembrane Ca influx is essential to the proper functioning of the central clock in the suprachiasmatic nucleus (SCN). In the rat SCN neurons, the clearance of somatic Ca following depolarization-induced Ca transients involves Ca extrusion via Na /Ca exchanger (NCX) and mitochondrial Ca buffering. Here we show an important role of intracellular Na in the regulation of [Ca ] in these neurons. The effect of Na loading on [Ca ] was determined with the Na ionophore monensin and the cardiac glycoside ouabain to block Na /K -ATPase (NKA). Ratiometric Na and Ca imaging was used to measure the change in [Na ] and [Ca ] , and cell-attached recordings to investigate the effects of monensin and ouabain on spontaneous firing. Our results show that in spite of opposite effects on spontaneous firing and basal [Ca ], both monensin and ouabain induced Na loading, and increased the peak amplitude, slowed the fast decay rate, and enhanced the slow decay phase of 20 mM K -evoked Ca transients. Furthermore, both ouabain and monensin preferentially enhanced nimodipine-insensitive Ca transients. Together, our results indicate that in the SCN neurons the NKA plays an important role in regulating [Ca ] , in particular, associated with nimodipine-insensitive Ca channels.
ISSN:1422-0067
1661-6596
1422-0067
DOI:10.3390/ijms20194868