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In-depth Physiological Analysis of Defined Cell Populations in Acute Tissue Slices of the Mouse Vomeronasal Organ
Published on: September 10, 2016
An osmosensitive voltage-gated K+ current in rat supraoptic neurons
Wenbo Zhang1, Daoyi Wang, Xiao-Hong Liu
1Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
The European Journal of Neuroscience
|June 4, 2009
Summary
Magnocellular neurosecretory cells (MNCs) in the hypothalamus use an osmosensitive outward potassium current (OKC) to regulate electrical activity. This OKC, mediated by K V 7/M-type channels, responds to changes in external osmolality.
Area of Science:
- Neuroscience
- Cell Physiology
- Molecular Biology
Background:
- Magnocellular neurosecretory cells (MNCs) in the hypothalamus are crucial for regulating fluid balance.
- Their electrical activity is modulated by external osmolality via osmosensitive ion channels.
Purpose of the Study:
- To identify and characterize an osmosensitive ion current in MNCs.
- To determine the molecular identity and functional role of this current in osmoregulation.
Main Methods:
- Whole-cell patch-clamp electrophysiology on isolated MNCs.
- Extracellular recordings in hypothalamic explant preparations.
- Reverse transcriptase-polymerase chain reaction and immunocytochemistry to identify ion channel expression.
Main Results:
- A novel osmosensitive outward potassium current (OKC) was identified in MNCs.
- The OKC is tetraethylammonium-insensitive, blocked by Ba(2+), linopirdine, and XE991, and enhanced by retigabine.
- MNCs express K V 7.2, 7.3, 7.4, and 7.5 channel subunits, suggesting M-type channels mediate the OKC.
- The OKC influences MNC firing rate in a hypothalamic explant preparation.
Conclusions:
- MNCs possess an osmosensitive K(+) current (OKC) that contributes to electrical activity regulation.
- This current is likely mediated by K V 7/M-type potassium channels.
- The OKC plays a role in how MNCs respond to changes in external osmolality.
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