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Dynamic activation of K(ATP) channels in rhythmically active neurons
M Haller1, S L Mironov, A Karschin
1Physiologisches Institut, Georg August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany. mirjam@neuro-physiol.med.uni-goettingen.de
The Journal of Physiology
|November 17, 2001
Summary
ATP-dependent K(+) channels (K(ATP) channels) in the brainstem respiratory center adjust neuronal excitability. These channels link neuronal activity to cellular metabolism, crucial for stable breathing under varying conditions.
Area of Science:
- Neuroscience
- Cellular Physiology
Background:
- The brainstem respiratory center generates rhythmic activity essential for life.
- Neuronal excitability must be dynamically adjusted to match metabolic demands.
- ATP-dependent K(+) channels (K(ATP) channels) are implicated in regulating neuronal excitability based on metabolic status.
Purpose of the Study:
- To investigate the role of K(ATP) channels in modulating respiratory neuron excitability.
- To determine if K(ATP) channels are expressed in respiratory neurons and synchronized with respiratory cycles.
Main Methods:
- Single-cell antisense RNA amplification-polymerase chain reaction (PCR) to detect gene expression.
- Single-channel recordings from brainstem slices of newborn mice.
- Inhibition of Na(+)-K(+)-ATPase with ouabain to assess channel activity dependence on ATP levels.
Main Results:
- Respiratory neurons co-express SUR1 and Kir6.2 subunits of K(ATP) channels.
- K(ATP) channel activity is synchronized with the respiratory cycle in inspiratory neurons.
- K(ATP) channel open probability fluctuates with submembrane ATP levels, reflecting metabolic state.
- Changes in respiratory rhythm and extracellular potassium affect K(ATP) channel activity.
Conclusions:
- K(ATP) channels are integral to the dynamic regulation of central respiratory neuron excitability.
- These channels continuously adjust neuronal activity across a wide range of metabolic conditions, from physiological to pathological energy depletion.