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Studies on intrategumental pH and its regulation in adult male Schistosoma mansoni

Published online by Cambridge University Press:  06 April 2009

R. A. Pax  and
J. L. Bennett
R. A. Pax
Affiliation:
Department of Zoology and Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA
J. L. Bennett
Affiliation:
Department of Zoology and Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA
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Summary

The intrategumental pH in adult male Schistosoma mansoni as measured with pH-sensitive microelectrodes is between 7.0 and 7.2, a value about one pH unit more alkaline than expected for equilibrium. This value is maintained for at least 4 h after isolation in media buffered with Hepes or CO2/ with or without serum present. CCCP (1 μM) and FCCP (10 μM) cause rapid acidification. DNP (1 mM) and Na-orthovanadate (1 mM) acidify but also cause significant depolarization of the tegument. NH (20 mM) depolarizes and acidifies the tegument with no evidence of transient alkalinization. High K+ (25 mM) accelerates the acidification. Removal of the NH+4 causes a large transient further acidification with recovery requiring as long as 40 min. High K+ (25 mM) delays the early stage of the recovery. Presence of CO2/HCO in the incubation medium does not accelerate the recovery rate nor does SITS (100 μM) inhibit the recovery. Intrategumental Na+ is elevated after an acid load and amiloride (3 mM) as well as low Na+ medium interfere with recovery from the acid load indicating that a Na+–H+ exchanger may be present in the tegumental membrane.

Keywords

Schistosoma mansonipHmembrane potentialtegument.
Type
Research Article
Information
Parasitology , Volume 101 , Issue 2 , October 1990 , pp. 219 - 226
Copyright
Copyright © Cambridge University Press 1990

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