Regulation of epithelial shunt conductance by the peptide leucokinin

Thomas L Pannabecker, Timothy K. Hayest, Klaus W. Beyenbach

Research output: Contribution to journalArticle

106 Citations (Scopus)

Abstract

Isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti spontaneously secrete NaCl, KCl and water across an epithelium of modest transepithelial resistance (40-80 Ωcm2) and high transepithelial voltage (30-70 mV, lumen positive). Transepithelial electrochemical potentials indicate that Na and K are secreted by active and Cl by passive transport mechanisms. The addition of synthetic leucokinin-VIII (LK-VIII, insect myotropic peptide) to the peritubular bath significantly increases the rates of transepithelial NaCl, KCl and water secretion. In parallel, LK-VIII depolarizes the transepithelial voltage from 59.3 to 5.7 mV, decreases the transepithelial resistance from 57.7 to 9.9 Ωcm2, and renders the basolateral and apical membrane voltages nearly equipotential (∼ -90 mV). Unilateral step changes of the [Cl] in the peritubular bath or tubule lumen elicit small transepithelial Cl diffusion potentials in the absence of LK-VIII but large transepithelial Cl diffusion potentials, up to 85% of Nernst equilibrium potentials, in the presence of LK-VIII. In Malpighian tubules treated with dinitrophenol for estimates of the shunt resistance Rsh, LK-VIII reduces Rsh from 52.5 to 5.8 ωcm2. Bilateral reductions of the Cl concentration in tubule lumen and peritubular bath fully restore Rsh to 55.8 Ωcm2in the presence of LK-VIII. LK-VIII has no effects when presented from the luminal side. These results suggest that LK-VIII increases the Cl conductance of the epithelial shunt via a receptor located at the basolateral side of the epithelium.

Original languageEnglish (US)
Pages (from-to)63-76
Number of pages14
JournalThe Journal of Membrane Biology
Volume132
Issue number1
DOIs
StatePublished - Feb 1993
Externally publishedYes

Fingerprint

Baths
Malpighian Tubules
Peptides
Epithelium
Dinitrophenols
Yellow Fever
Water
Aedes
Culicidae
Insects
Membranes

Keywords

  • dinitrophenol
  • epithelial shunt pathway chloride conductance
  • leucokinin-VIII
  • Malpighian tubule
  • myotropic and diuretic peptides

ASJC Scopus subject areas

  • Physiology
  • Cell Biology
  • Biophysics

Cite this

Regulation of epithelial shunt conductance by the peptide leucokinin. / Pannabecker, Thomas L; Hayest, Timothy K.; Beyenbach, Klaus W.

In: The Journal of Membrane Biology, Vol. 132, No. 1, 02.1993, p. 63-76.

Research output: Contribution to journalArticle

Pannabecker, Thomas L ; Hayest, Timothy K. ; Beyenbach, Klaus W. / Regulation of epithelial shunt conductance by the peptide leucokinin. In: The Journal of Membrane Biology. 1993 ; Vol. 132, No. 1. pp. 63-76.
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