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Quantitative relationship between Kv4.2 mRNA and A-type K+ current in rat striatal cholinergic interneurons during
Satoko Hattori1, Fujio Murakami, Wen-Jie Song
1Department of Electronic Engineering, Graduate School of Engineering, and Neuroscience Laboratories, Graduate School of Frontier Bioscience, Osaka University, Suita 565-0871, Japan.
Journal of Neurophysiology
|July 5, 2003
Summary
Kv4.2 channels are crucial for the A-type current in developing rat striatal cholinergic interneurons. Their expression increases postnatally, mirroring A-type current development.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Neuronal firing is regulated by channel density, influenced by developmental transcriptional and translational control.
- Adult rat striatal cholinergic interneurons express Kv4.1 and Kv4.2 mRNAs and possess a significant A-type current, with Kv4.2 implicated in its production.
Purpose of the Study:
- To investigate the developmental roles of Kv4.2 and Kv4.1 in shaping the A-type current of rat striatal cholinergic interneurons during postnatal development.
Main Methods:
- Patch-clamp electrophysiology to record A-type currents.
- Semi-quantitative single-cell reverse transcription-polymerase chain reaction (RT-PCR) to assess Kv4.1 and Kv4.2 mRNA expression levels.
Main Results:
- A-type current was present at birth and increased with age, plateauing around 3 weeks postnatally.
- Kv4.2 mRNA was detected at birth and its expression rose exponentially with age, stabilizing by 3 weeks.
- Kv4.1 mRNA was undetectable in the first postnatal week and showed no clear age-dependent expression trend.
Conclusions:
- Kv4.2 plays a critical role in generating the A-type current in striatal cholinergic interneurons throughout postnatal development.
- The developmental upregulation of Kv4.2 expression correlates with the maturation of the A-type current in these neurons.