Biophysical properties of gap junction channels formed by mouse connexin40 in induced pairs of transfected human HeLa cells.

摘要: A clone of human HeLa cells stably transfected with mouse connexin40 DNA was used to examine gap junctions. Two separate were brought into physical contact each other ("induced cell pair") allow insertion junction channels and, hence, formation a junction. The intercellular current flow measured dual voltage-clamp method. This approach enabled us study the electrical properties (cell pairs single channel) and junctions many channels). We found that exhibited multiple conductances, main state (gamma j(main state)), several substates j(substates)), residual j (residual closed j(closed state)). gamma state) 198 pS, j(residual 36 pS (temperature, 36–37 degrees C; pipette solution, potassium aspartate). Both insensitive transjunctional voltage, Vj. transitions between an open (i.e., state, substate, or slow (15–45 ms); those substate fast (1–2 ms). Under steady-state conditions, channel probability, Po, decreased in sigmoidal manner from 1 0 (Boltzmann fit: Vj,o = -44 mV; z 6). temperature coefficient, Q10, for 1.2 1.3, respectively (p