Single channel Ca2+ currents inHelix pomatia neurons

Publisher Website
Google Scholar
Abstract
Unitary Ca2+ currents of TEA injected Helix neurons were recorded in the “Giga seal” situation (6, 7) from microscopic membrane patches exposed to 50 mM [Ca2+]o, O [Na+]o, 20 mM [TEA+]o and 2.5 μM [TTX]o. Constant field assumptions yield a channel permeability of 2.9±1.0×10−14 cm3s−1 corresponding to slope conductances of 5 to 15 pS between 0 and −30 mV. Frequency of occurrence of the units strongly increased with depolarization. Mean open time of the Ca2+ channels was about 3 ms without obvious dependence on voltage. A similar open time was seen with [Ba2+]o, yielding about double the current strength when compared with [Ca2+]o.