TY - JOUR
T1 - Oscillations of voltage and resistance in Malpighian tubules of Aedes aegypti
AU - Beyenbach, Klaus W.
AU - Aneshansley, Daniel J.
AU - Pannabecker, Thomas L.
AU - Masia, Ricard
AU - Gray, David
AU - Yu, Ming Jiun
N1 - Funding Information:
The authors thank the National Science Foundation for making this work possible via grants IBN 9220464 and IBN 9604394 awarded to K. W. Beyenbach. The senior author (Beyenbach) thanks Sandy Hellman for past lessons in epithelial electrophysiology and Wilhelm Elmore for assistance with computer hard- and software.
PY - 2000/3
Y1 - 2000/3
N2 - The transepithelial voltage (V(t)) of isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti spontaneously oscillates in more than half the tubules. Typically, V(t) decreases and then rises at a frequency of 2 oscillations/min with a duration of 16 s. In 6 isolated perfused tubules studied in detail, V(t), oscillates between 50.5 mV and 15.7 mV in parallel with (1) oscillations of the transepithelial resistance (R(t)) between 7.61 kΩcm and 3.63 kΩcm, (2) oscillations of the basolateral membrane voltage of principal cells between -56.7 mV and -72.2 mV, and (3) oscillations of the apical membrane voltage between 107.2 mv and 87.8 mV. The oscillations are dependent on the Cl concentration in the extracellular solutions. As R(t) decreases during the oscillations V(t) goes to the transepithelial equilibrium potential of Cl (E(cl)) indicating transient changes in transepithelial Cl conductance as the mechanism of voltage and resistance oscillations. Since the largest voltage oscillations take place across the whole epithelium and not across cell membranes, oscillating Cl conductances are localized to a single transepithelial Cl diffusion barrier such as the paracellular pathway. This conclusion is supported by the analysis of electrically equivalent circuits that identify the shunt pathway as the site of oscillating Cl conductances. (C) 2000 Elsevier Science Ltd.
AB - The transepithelial voltage (V(t)) of isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti spontaneously oscillates in more than half the tubules. Typically, V(t) decreases and then rises at a frequency of 2 oscillations/min with a duration of 16 s. In 6 isolated perfused tubules studied in detail, V(t), oscillates between 50.5 mV and 15.7 mV in parallel with (1) oscillations of the transepithelial resistance (R(t)) between 7.61 kΩcm and 3.63 kΩcm, (2) oscillations of the basolateral membrane voltage of principal cells between -56.7 mV and -72.2 mV, and (3) oscillations of the apical membrane voltage between 107.2 mv and 87.8 mV. The oscillations are dependent on the Cl concentration in the extracellular solutions. As R(t) decreases during the oscillations V(t) goes to the transepithelial equilibrium potential of Cl (E(cl)) indicating transient changes in transepithelial Cl conductance as the mechanism of voltage and resistance oscillations. Since the largest voltage oscillations take place across the whole epithelium and not across cell membranes, oscillating Cl conductances are localized to a single transepithelial Cl diffusion barrier such as the paracellular pathway. This conclusion is supported by the analysis of electrically equivalent circuits that identify the shunt pathway as the site of oscillating Cl conductances. (C) 2000 Elsevier Science Ltd.
KW - Malpighian tubules
KW - Paracellular chloride conductance
KW - Transepithelial voltage and resistance oscillations
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U2 - 10.1016/S0022-1910(99)00185-7
DO - 10.1016/S0022-1910(99)00185-7
M3 - Article
AN - SCOPUS:0034007241
SN - 0022-1910
VL - 46
SP - 321
EP - 333
JO - Journal of Insect Physiology
JF - Journal of Insect Physiology
IS - 3
ER -