Fluctuations of the Ca2+-activated K+ current in Aplysia neurones.
Fluctuations of the Ca2+-activated K+ current were measured in identified Aplysia neurones under voltage clamp conditions. The amplitude of IK,Ca was manipulated by ionophoretic injections of Ca2+. At small amplitudes of Ca2+-activated outward currents the variance of the Ca2+-activated current fluctuations increases linearly with the mean outward current. The single-channel conductance estimated from the variance of the fluctuations and the mean outward current is 11 +/- 3 pS at -30 mV. Power spectra of the Ca2+-activated K+ current can be fitted by the sum of two Lorentzian components with corner frequencies of about 10 Hz and 120 Hz.
D000818:Animals; D001048:Aplysia / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D006372:Helix, Snails / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects*; D009474:Neurons / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*
D007473:Ion Channels; D011188:Potassium; D002118:Calcium