Studies on intrategumental pH and its regulation in adult male Schistosoma mansoni.
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/HCO3- with or without serum present. CCCP (1 microM) and FCCP (10 microM) cause rapid acidification. DNP (1 mM) and Na-orthovanadate (1 mM) acidify but also cause significant depolarization of the tegument. NH4+ (20 mM) depolarizes and acidifies the tegument with no evidence of transient alkalinization. High K+ (25 mM) accelerates the acidification. Removal of the NH4+ 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/HCO3- in the incubation medium does not accelerate the recovery rate nor does SITS (100 microM) 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.
Pax
R A
RA
Department of Zoology, Michigan State University, East Lansing 48824.
Bennett
J L
JL
D000818:Animals; D003470:Culture Media; D006863:Hydrogen-Ion Concentration; D008297:Male; D008839:Microelectrodes; D012550:Schistosoma mansoni / Q000378:metabolism*
D003470:Culture Media