2002年11月
Identification of the Ca2+ conductance responsible for K+-induced backward swimming in paramecium caudatum
JOURNAL OF MEMBRANE BIOLOGY
- ,
- 巻
- 190
- 号
- 2
- 開始ページ
- 159
- 終了ページ
- 165
- 記述言語
- 英語
- 掲載種別
- DOI
- 10.1007/s00232-002-1031-7
- 出版者・発行元
- SPRINGER-VERLAG
Membrane potential responses of Paramecium caudatum to an application of K+-rich solution were examined to understand the mechanisms underlying K+-induced backward swimming. A wildtype cell impaled by a microelectrode produced action potentials followed by a sustained depolarization in response to an application of a K+-rich test solution. After termination of the application, a prolongation of the depolarization (depolarizing after-potential) took place. Behavioral mutants incapable of exhibiting K+-induced backward swimming did not show depolarizing afterpotentials. Upon short application of K+-rich solution, the timing and duration of the ciliary reversal of the wildtype cell coincided well with the K+-induced depolarization. The duration of the depolarizing afterpotential decreased as the duration of the application increased. The depolarizing afterpotential recovered slowly after it had been suppressed by a preceding application of the K+-rich solution. By injection of an outward current into the wild-type cell, the action potentials were evoked normally during the period when the K+-induced depolarizing afterpotential was suppressed. We concluded that the prolongation of the depolarizing membrane potential response following the application of the K+-rich solution represents the Ca2+ conductance responsible for the K+-induced backward swimming in P. caudatum and that the characteristics of the K+-induced Ca2+ conductance are distinct from those of the Ca2+ conductance responsible for the action potentials.
- リンク情報
- ID情報
-
- DOI : 10.1007/s00232-002-1031-7
- ISSN : 0022-2631
- Web of Science ID : WOS:000179699000008