Single and combined effects of barium and bumetanide on transepithelial electrolyte and fluid secretion in isolated Malpighian tubules of the yellow fever mosquito, Aedes aegypti
| . | . | Electrolytes in secreted fluid . | . | . | Transepithelial . | . | Principal cell . | . | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Fluid secretion (nl min-1) . | [Na+] (mmol l-1) . | [K+] (mmol l-1) . | [Cl-] (mmol l-1) . | Voltage (mV) . | Resistance (kΩcm) . | Basolateral membrane voltage (mV) . | Input resistance (kΩ) . | ||||
| Control | 0.84±0.03 (7) | 116.8±16.2 (7) | 119.0±27.2 (7) | 197.7±8.3 (7) | 19.4±8.3 (11) | 6.37±0.64 (11) | -75.2±4.7 (12) | 363.7±18.4 (12) | ||||
| Ba2+ (0.5 mmol l-1) | 0.37±0.03*(7) | 144.6±7.3*(7) | 54.3±28.7*(7) | 192.4±10.3 (7) | 17.2±3.6*(11) | 6.87±0.81*(11) | -88.2±5.2*(12) | 516.3±29.9*(12) | ||||
| Control1 | 1.15±0.08 (14) | 110.4±6.8 (14) | 88.0±6.8 (14) | 221.1±5.2 (14) | 52.1±8.1 (8) | 11.6±2.0 (8) | NM | NM | ||||
| Bumetanide (0.1 mol l-1)1 | 1.01±0.14 (14) | 169.5±9.2*(14) | 33.2±7.1*(14) | 223.0±5.0 (14) | 64.6±7.3*(8) | 12.4±1.8*(8) | NM | NM | ||||
| Control | 0.61±0.02 (6) | 93.8±8.8 (6) | 55.1±8.7 (6) | 150.3±9.9 (6) | 30.4±8.1 (7) | 11.0±2.1 (7) | -78.4±4.6 (6) | 314.9±27.9 (6) | ||||
| Ba2+ plus bumetanide | 0.06±0.02*(6) | 120.4±5.1*(6) | 25.3±2.4*(6) | 140.5±8.7 (6) | 38.2±3.0*(7) | 13.6±2.1*(7) | -59.3±6.5*(6) | 464.9±39.0*(6) | ||||
| . | . | Electrolytes in secreted fluid . | . | . | Transepithelial . | . | Principal cell . | . | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Fluid secretion (nl min-1) . | [Na+] (mmol l-1) . | [K+] (mmol l-1) . | [Cl-] (mmol l-1) . | Voltage (mV) . | Resistance (kΩcm) . | Basolateral membrane voltage (mV) . | Input resistance (kΩ) . | ||||
| Control | 0.84±0.03 (7) | 116.8±16.2 (7) | 119.0±27.2 (7) | 197.7±8.3 (7) | 19.4±8.3 (11) | 6.37±0.64 (11) | -75.2±4.7 (12) | 363.7±18.4 (12) | ||||
| Ba2+ (0.5 mmol l-1) | 0.37±0.03*(7) | 144.6±7.3*(7) | 54.3±28.7*(7) | 192.4±10.3 (7) | 17.2±3.6*(11) | 6.87±0.81*(11) | -88.2±5.2*(12) | 516.3±29.9*(12) | ||||
| Control1 | 1.15±0.08 (14) | 110.4±6.8 (14) | 88.0±6.8 (14) | 221.1±5.2 (14) | 52.1±8.1 (8) | 11.6±2.0 (8) | NM | NM | ||||
| Bumetanide (0.1 mol l-1)1 | 1.01±0.14 (14) | 169.5±9.2*(14) | 33.2±7.1*(14) | 223.0±5.0 (14) | 64.6±7.3*(8) | 12.4±1.8*(8) | NM | NM | ||||
| Control | 0.61±0.02 (6) | 93.8±8.8 (6) | 55.1±8.7 (6) | 150.3±9.9 (6) | 30.4±8.1 (7) | 11.0±2.1 (7) | -78.4±4.6 (6) | 314.9±27.9 (6) | ||||
| Ba2+ plus bumetanide | 0.06±0.02*(6) | 120.4±5.1*(6) | 25.3±2.4*(6) | 140.5±8.7 (6) | 38.2±3.0*(7) | 13.6±2.1*(7) | -59.3±6.5*(6) | 464.9±39.0*(6) | ||||
Values are means ± s.e.m. (N). For fluid and electrolyte data collected by the method of Ramsay, each tubule served as its own control. Secreted fluid was collected after the usual 30 min control period and then again 20-70 min later after barium and/or bumetanide had been added to the peritubular Ringer. Voltage is measured with respect to ground in the peritubular bath.
Data from Hegarty et al.(1991)
P<0.05; NM, not measured