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Spontaneous miniature outward currents in mechanically dissociated rat Meynert neurons
Author(s) -
Arima Junichi,
Matsumoto Nozomu,
Kishimoto Kiyonori,
Akaike Norio
Publication year - 2001
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2001.00099.x
Subject(s) - ryanodine receptor , apamin , endoplasmic reticulum , biophysics , chemistry , channel blocker , extracellular , serca , patch clamp , medicine , endocrinology , microbiology and biotechnology , electrophysiology , potassium channel , neuroscience , calcium , biology , atpase , biochemistry , enzyme , organic chemistry
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 Ca 2+ ‐activated K + (SK) channels, but not by blockers for other types of Ca 2+ ‐activated K + channel. 3 Ryanodine (10‐100 μ m ) reduced both the amplitude and frequency of SMOCs. Caffeine (1 m m ) increased the SMOC frequency. Blockers of the sarco/endoplasmic reticulum Ca 2+ ‐ATPase completely abolished SMOCs, indicating a requirement for functioning sarco/endoplasmic reticulum (SR/ER) Ca 2+ stores. 4 Both Cd 2+ ‐containing and Ca 2+ ‐free solutions partially inhibited SMOC frequency, a result which suggests that Ca 2+ influx contributes to, but is not essential for, SMOC generation. 5 Thus, SMOCs are SK currents linked to ryanodine‐ and caffeine‐sensitive SR/ER Ca 2+ stores, and are only indirectly influenced by extracellular Ca 2+ influx. The development of this new, minimally invasive mechanical dissociation method has revealed that SMOCs are common in native CNS neurons.