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Electrical Events Correlated with Contractile Vacuole Activity in the Suctorian, Heliophrya
Author(s) -
EAGLES DOUGLAS A.,
GREGG ROBERT A.,
SPOON DONALD M.
Publication year - 1980
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1980.tb05390.x
Subject(s) - depolarization , membrane potential , vacuole , biophysics , contractile vacuole , intracellular , membrane , chemistry , electrophysiology , resting potential , biology , biochemistry , neuroscience , cytoplasm
SYNOPSIS. The surface membrane potentials of suctorian genus Heliophrya were studied with intracellular electrodes. Resting membrane potentials averaged ‐32 mV, and spontaneous depolarizing potentials occurring at apparently random intervals and having a variety of waveforms were routinely observed. Such spontaneous potentials were correlated in time with visually monitored contractile vacuole activity. Individual contractile vacuoles had unique, although somewhat variable, electrical signatures. In the presence of an intracellular electrode all vacuoles contracted independently, but at approximately the same frequency. The amplitude of the electrical potentials increased when the membrane was hyperpolarized and decreased when it was depolarized. The sign of such potentials reversed at between ‐10 mV and the zero membrane potential. A 20% decrease in the membrane resistance was measured at the peak of the spontaneous depolarizing potentials.