CONTRIBUTIONS OF FAST AND SLOW POTASSIUM OUTWARD CURRENTS TO REPOLARIZATION OF THE ACTION-POTENTIAL IN EUPLOTES-VANNUS

Autor(en): WESTERMANN, R
KRUPPEL, T
LUEKEN, W
Stichwörter: BEHAVIOR; CILIOPHORA; CONJUGATION; HYPOTRICHIDA; MARINE CILIATE; Microbiology; MUTANT
Erscheinungsdatum: 1990
Herausgeber: NENCKI INST EXPERIMENTAL BIOLOGY
Journal: ACTA PROTOZOOLOGICA
Volumen: 29
Ausgabe: 4
Startseite: 305
Seitenende: 313
Zusammenfassung: 
In the marine hypotrichous Euplotes vannus, fast and slowly activating potassium outward currents (I(K fast), I(K slow) were studied in current- and in voltage-clamp, by use of a single-microelectrode equipment. Their contributions to regulation of the membrane potential were isolated by i) blocking Ca2+-dependent I(K slow) by TEA or EGTA and ii) inactivation of I(K fast) via a two-pulse protocol. Current activation was tested in voltage ramps that mimicked the membrane response to current injection. I(K fast) limits the action potential amplitude and causes small initial repolarization. I(K slow) continues repolarization and is responsible, due to delayed activation and deactivation, for damped potential oscillation.
ISSN: 00651583

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