Single Ca2+-activated K+channels in excised membrane patches of hamster oocytes

✍ Scribed by S. Yoshida; S. Plant; A. I. McNiven; C. R. House

• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 317 KB
• Volume: 415
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00373637

✦ Synopsis

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 CaZ+-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 Ca 2+ 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.