Single Ca2(+)-activated K+ channels in excised membrane patches of hamster oocytes.
The properties of the Ca2(+)-activated K+ channel in unfertilized hamster oocytes were investigated at the single-channel level using inside-out excised membrane patches. The results indicate a new type of Ca2(+)-activated K+ channel which has the following characteristics: (1) single-channel conductance of 40-85 pS for outward currents in symmetrical K+ (150 mM) solutions. (2) inward currents of smaller conductance (10-50 pS) than outward currents, i.e. the channel is outwardly rectified in symmetrical K+ solutions, (3) channel activity dependent on the internal concentration of free Ca2+ and the membrane potential, (4) modification of the channel activity by internal adenosine 5' diphosphate (0.1 mM) producing a high open probability regardless of membrane potential.
Yoshida
S
S
Department of Preclinical Veterinary Sciences, University of Edinburgh, UK.
Plant
S
S
McNiven
A I
AI
House
C R
CR
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D006224:Cricetinae; D005260:Female; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D009865:Oocytes / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*
D015221:Potassium Channels; D002118:Calcium