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Na(+)-activated nonselective cation channels in primary olfactory neurons
1Whitney Laboratory, University of Florida, St. Augustine 32086, USA.
Journal of Neurophysiology
|May 1, 1995
Summary
Researchers discovered a novel cation channel in lobster olfactory neurons activated by intracellular sodium (Na+). This channel, permeable to Na+, K+, and Li+, influences neuronal excitability and response to odors.
Area of Science:
- Neuroscience
- Ion Channel Physiology
- Olfactory Receptor Neuron Research
Background:
- Olfactory receptor neurons (ORNs) are crucial for detecting odors.
- Understanding the ion channels involved in ORN function is key to deciphering olfactory signaling.
Purpose of the Study:
- To characterize a novel cation channel identified in cultured lobster ORNs.
- To investigate the activation, permeability, and modulatory properties of this new channel.
Main Methods:
- Utilized excised inside-out patch recordings from lobster ORNs.
- Performed electrophysiological analysis to determine channel kinetics and ion selectivity.
Main Results:
- Identified a cation channel activated by intracellular sodium (Na+i) with a sigmoidal dependence (Hill coefficient of 3.1).
- The channel exhibits equal permeability to Na+, K+, and Li+, with a slope conductance of 107 pS.
- Channel gating is influenced by voltage, intracellular Na+ ([Na+]i), and extracellular Na+ ([Na+]o).
- Intracellular Ca2+ and Mg2+ modulate channel activity, affecting open probability and single-channel amplitude.
- Ba2+ blocks the channel, while Cs+ and amiloride do not.
Conclusions:
- A novel, multi-ion cation channel activated by intracellular Na+ has been identified in lobster ORNs.
- This channel likely plays a role in regulating neuronal excitability and odor-induced depolarization.