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Voltage-gated currents in muscle cells of Schistosoma mansoni

Published online by Cambridge University Press:  06 April 2009

T. A. Day ,
N. Orr ,
J. L. Bennett  and
A. Pax
T. A. Day
Affiliation:
Department of Zoology and Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
N. Orr
Affiliation:
Department of Zoology and Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
J. L. Bennett
Affiliation:
Department of Zoology and Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
A. Pax
Affiliation:
Department of Zoology and Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
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Summary

Three morphologically distinct types of muscle fibres isolated from the platyhelminth Schistosoma mansoni have been studied with whole cell current- and voltage-clamp techniques. Fibres showed a marked time-dependent decrease in membrane resistance in response to depolarizing current injections. Voltage-clamp experiments revealed the presence of two distinct voltage-gated outward currents. The most prominent current is a slowly activating, slowly and incompletely inactivating potassium current similar to delayed rectifier currents which have been described in a variety of cell types from a variety of organisms. Also present is a faster activating, quickly and completely inactivating potassium current that shares functional characteristics with ‘A’-currents. All three of the cell types studied possess a delayed rectifier current, but only two of the three types have ‘A’-currents. Though depolarization with high K+ leads to contraction of the dispersed fibres, no voltage-gated inward currents could be detected by whole cell voltage-clamp under any of our conditions.

Keywords

Schistosoma mansoniPlatyhelminthmusclepatch-clampdelayed rectifier‘A’-current
Type
Research Article
Information
Parasitology , Volume 106 , Issue 5 , June 1993 , pp. 471 - 477
Copyright
Copyright © Cambridge University Press 1993

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References

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