Spontaneous miniature outward currents in mechanically dissociated rat Meynert neurons

J. Arima, N. Matsumoto, K. Kishimoto, N. Akaike

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Abstract

1. Spontaneous miniature outward currents (SMOCs) were observed in mechanically dissociated rat Meynert neurons using nystatin perforated patch recordings under voltage-clamp conditions. 2. SMOCs were blocked by apamin, a selective blocker of small conductance Ca2+-activated K+ (SK) channels, but not by blockers for other types of Ca2+-activated K+ channel. 3. Ryanodine (10-100 μM) reduced both the amplitude and frequency of SMOCs. Caffeine (1 mM) increased the SMOC frequency. Blockers of the sarco/endoplasmic reticulum Ca2+-ATPase completely abolished SMOCs, indicating a requirement for functioning sarco/endoplasmic reticulum (SR/ER) Ca2+ stores. 4. Both Cd2+-containing and Ca2+-free solutions partially inhibited SMOC frequency, a result which suggests that Ca2+ influx contributes to, but is not essential for, SMOC generation. 5. Thus, SMOCs are SK currents linked to ryanodine- and caffeine-sensitive SR/ER Ca2+ stores, and are only indirectly influenced by extracellular Ca2+ influx. The development of this new, minimally invasive mechanical dissociation method has revealed that SMOCs are common in native CNS neurons.

Original languageEnglish
Pages (from-to)99-107
Number of pages9
JournalJournal of Physiology
Volume534
Issue number1
DOIs
Publication statusPublished - Jul 1 2001

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All Science Journal Classification (ASJC) codes

  • Physiology

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