PMID- 16553612
OWN - NLM
STAT- MEDLINE
DCOM- 20060530
LR  - 20131121
IS  - 0953-816X (Print)
IS  - 0953-816X (Linking)
VI  - 23
IP  - 6
DP  - 2006 Mar
TI  - Calcium permeability and flux through osmosensory transduction channels of 
      isolated rat supraoptic nucleus neurons.
PG  - 1491-500
AB  - Hypertonic stimuli delivered into the supraoptic nucleus provoke neuropeptide 
      release from the somata of magnocellular neurosecretory cells (MNCs) in the 
      presence of tetrodotoxin, suggesting that such stimuli can increase intracellular 
      calcium concentration ([Ca2+]i) in the absence of action potentials. We therefore 
      examined whether the stretch-inhibited cation (SIC) channels of MNCs can mediate 
      calcium influx. Whole-cell recordings were made in MNCs isolated from the 
      supraoptic nuclei of adult rats. Measurements of reversal potentials in different 
      solutions revealed that the current induced by a suction-evoked decrease in cell 
      volume (ISIC) displays a selectivity sequence for monovalent cations of 
      K+>Cs+>Na+>NMDG+. The permeability of SIC channels to Ca2+, relative to Na+, was 
      approximately 5. In the presence of physiological concentrations of external Na+ 
      and K+, the amplitude of inward ISIC was reduced dose-dependently by external 
      Ca2+ with an IC50 of 4.9 mM. This was not due to reduced suction-evoked volume 
      changes or to an accumulation of [Ca2+]i. Confocal imaging of cytoplasmic Calcium 
      Green-1 fluorescence revealed that activation of ISIC significantly increases 
      [Ca2+]i in physiological solutions. This effect is absent in Ca2+-free solution, 
      or when Gd3+ (300 microM) is added to Ca2+-containing solution. Part of this 
      effect is inhibited in the presence of dantrolene (10 microM) and heparin (4 
      mg/mL), suggesting that release from intracellular Ca2+ stores participates in 
      suction-evoked Ca2+ signalling. These observations indicate that SIC channels are 
      highly permeable to Ca2+, mediate significant Ca2+ entry and release of Ca2+ from 
      internal stores under conditions when the volume of MNCs is decreased.
FAU - Zhang, Zizhen
AU  - Zhang Z
AD  - Centre for Research in Neuroscience, Research Institute of the McGill University 
      Health Center, 1650 Cedar Avenue, Montreal, QC, Canada, H3G 1A4.
FAU - Bourque, Charles W
AU  - Bourque CW
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - France
TA  - Eur J Neurosci
JT  - The European journal of neuroscience
JID - 8918110
RN  - 0 (Calcium Channels)
RN  - 0 (Cations)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Algorithms
MH  - Animals
MH  - Calcium/*metabolism
MH  - Calcium Channels/*metabolism
MH  - Cations/metabolism
MH  - Cell Separation
MH  - Electrophysiology
MH  - Mechanoreceptors/*physiology
MH  - Neurons/*metabolism
MH  - Neurosecretory Systems/cytology/physiology
MH  - Osmolar Concentration
MH  - Patch-Clamp Techniques
MH  - Rats
MH  - Rats, Long-Evans
MH  - Signal Transduction/*physiology
MH  - Supraoptic Nucleus/cytology/*metabolism
EDAT- 2006/03/24 09:00
MHDA- 2006/05/31 09:00
CRDT- 2006/03/24 09:00
PHST- 2006/03/24 09:00 [pubmed]
PHST- 2006/05/31 09:00 [medline]
PHST- 2006/03/24 09:00 [entrez]
AID - EJN4670 [pii]
AID - 10.1111/j.1460-9568.2006.04670.x [doi]
PST - ppublish
SO  - Eur J Neurosci. 2006 Mar;23(6):1491-500. doi: 10.1111/j.1460-9568.2006.04670.x.