THE DEPOLARIZING MECHANORECEPTOR POTENTIAL AND CA/MG RECEPTOR-CURRENT OF THE MARINE CILIATE EUPLOTES VANNUS

Autor(en): KRUPPEL, T
RABE, H
DUMMLER, B
LUEKEN, W
Stichwörter: Behavioral Sciences; CALCIUM CURRENT; CHANNEL; CONJUGATION; ELECTRICAL RESPONSES; EUPLOTES VANNUS; INACTIVATION; MAGNESIUM CURRENT; MECHANORECEPTION; MEMBRANE CURRENTS; Neurosciences; Neurosciences & Neurology; PARAMECIUM; Physiology; STYLONYCHIA; Zoology
Erscheinungsdatum: 1995
Herausgeber: SPRINGER VERLAG
Journal: JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY
Volumen: 177
Ausgabe: 4
Startseite: 511
Seitenende: 517
Zusammenfassung: 
The anterior depolarizing mechanoreceptor potential and the correlated receptor currents have been studied in the marine ciliate Euplotes vannus. Mechanical stimuli that mimicked cell-cell collisions depolarized the resting potential of about - 25 mV to maximally - 5 mV, with a speed of 1.2 mV/ms, a delay to the stimulus of about 15 ms, and a repolarization within 30 to 300 ms. The power-stroke direction of the cirri-beat reversed from backward to forward during this response. The receptor current rose to an average amplitude of 1.4 nA with a speed of 0.1-0.3 nA/ms and decayed with a single exponential time course with a time constant between 7 and 9 ms. Similar current-reversal potentials, after substitution of extracellular Ca2+ by Mg2+ and vice versa, indicate that the mechanically activated conductance is identical for Ca2+ or Mg2+. The current can be carried by Ba2+ as well, but not by K+ or Na+. Decirriation experiments have shown that the mechanosensitivity is located within the soma membrane.
ISSN: 03407594

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