Fluid Balance in the Argasid Tick, Ornithodorus Moubata, Fed On Modified Blood Meals (original) (raw)
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Ion and Water Balance in the Ixodid Tick Dermacentor Andersoni
Journal of Experimental Biology
1. Of the total meal imbibed by female Dermacentor andersoni during the normal adult feeding cycle, about 80% is excreted. Of the total water excreted by the tick, 75% is removed by salivation, less than 3% is evaporated from the integument and spiracles, and the remainder is lost via the anus. 2. Of the total excreted sodium and potassium, 4 and 82% respectively are lost via the anus. The remainder in each case is presumed excreted via the salivary glands. 3. The ionic and osmotic concentrations of the haemolymph and saliva stabilize at constant values by the third or fourth day of feeding. The volume of extracellular fluid is constantly maintained at 23% of the body weight, even though the total body weight increases 75 times over the unfed weight, and the volume of excreted fluid passing through the haemolymph is about ten times the haemolymph volume at repletion.
Fish Physiology and Biochemistry, 2006
The levels of various ions (Na+, Cl−, Ca2+, Mg2+, K+) in the fluid phase of the gastrointestinal contents and of the plasma were determined in four teleosts with different feeding habits: traira (Hoplias malabaricus), hassar (Hoplosternum littorale), silver catfish (Rhamdia quelen), and grass carp (Ctenopharyngodon idella). The results showed that most ionic levels in the fluid phase of the gastrointestinal tract seem to be affected by feeding habit and that these levels can be different from those found in the plasma. In practical terms, these results suggest that ionic levels of the gastrointestinal contents should be considered when preparing solutions for studies of intestinal absorption in fishes.
The excretion of NaCl and KCl loads in mosquitoes. 1. Control data
American journal of physiology. Regulatory, integrative and comparative physiology, 2014
The handling of Na(+) and K(+) loads was investigated in isolated Malpighian tubules and in whole mosquitoes of Aedes aegypti. Isolated Malpighian tubules bathed in Na(+)-rich Ringer solution secreted Na(+)-rich fluid, and tubules bathed in K(+)-rich Ringer solution secreted K(+)-rich fluid. Upon Na(+) loading the hemolymph, the mosquito removed 77% the injected Na(+) within the next 30 min. The rapid onset and magnitude of this diuresis and the excretion of more Na(+) than can be accounted for by tubular secretion in vitro is consistent with the release of the calcitonin-like diuretic hormone in the mosquito to remove the Na(+) load from the hemolymph. Downstream, K(+) was reabsorbed with water in the hindgut, which concentrated Na(+) in excreted urine hyperosmotic to the hemolymph. Upon K(+) loading the hemolymph, the mosquito took 2 h to remove 100% of the injected K(+) from the hemolymph. The excretion of K(+)-rich isosmotic urine was limited to clearing the injected K(+) from t...
Ion transport in the intestine ofGobius niger in both isotonic and hypotonic conditions
Journal of Experimental Zoology, 2004
Ion transport in the intestine of Gobius niger, a euryhaline teleost, was studied in both isotonic and hypotonic conditions. Isolated tissues, mounted in Ussing chambers and bilaterally perfused with isotonic Ringer solution, developed a serosa negative transepithelial voltage and a short circuit current indicating a net negative current in absorptive direction. Bilateral removal of Cl− and Na+ from the bathing solutions as well as the luminal removal of K+ in the presence of Ba2+(10−3 M) almost abolished both Vt and Isc. Similar results were obtained by adding bumetanide (10−5M) to the luminal bath while other inhibitors of Cl− transport mechanisms were ineffective. These observations suggest that salt absorption begins with a coupled entry of Na+, Cl−, and K+ across the apical membrane; a Ba2+inhibitable K+ conductance, demonstrated also by micropuncture experiments, recycles the ion into the lumen. Salt entry into the cell is driven by the operation of the basolateral Na+/K+-ATPase since serosal ouabain (10−4M) completely abolished both Vt and Isc; this pump also completes the Na+ absorption. The inhibitory effect of both serosal bumetanide (10−4M) and SITS (5˙10−4M) suggests that Cl− would leave the cell via the KCl cotransport, the Cl/HCO3−antiport and/or conductive pathways. Bilateral exposure of tissues to hypotonic media produced a reduction of both the transepithelial voltage and the short circuit current probably due to the activation of homeostatic ionic fluxes involved in cell volume regulation. The results of experiments with both isolated enterocytes and intestine exposed to hypotonic solution suggested that the recovery of cell volume, after the initial cell swelling, involves a parallel opening of K+ and Cl− channels to facilitate net solute and water effluxes from the cell. J. Exp. Zool. 301A:49–62, 2004. © 2004 Wiley-Liss, Inc.
Absorption of Fluid by the Midgut of Rhodnius
Journal of Experimental Biology, 1981
1. Isolated midguts of 5th-instar Rhodnius prolixus will transport fluid from the lumen that is close to iso-osmotic with the luminal contents. 2. The transported fluid contains sodium and chloride ions as its major constituents. 3. Fluid transport can be attributed to active transport of sodium ions from the lumen. The haemolymph side of the epithelium, towards which transport is directed, is at a potential positive with respect to the lumen; this potential difference is greatly increased if the lumen contains only impermeant anions, and the rate of fluid transport is strongly dependent on the concentration of sodium ions in the luminal fluid. 4. The rate of fluid transport is increased approximately six times by treatment with 5-hydroxytryptamine (2×10−7M) or cyclic AMP (2x−3M). The transepithelial potential is increased by such treatment but the major effects are on the short-circuit current, which increases by about five times, and on the electrical resistance of the epithelium,...