Unique electrophysiological effects of dinitrophenol in Malpighian tubules

T. L. Pannabecker, D. J. Aneshansley, K. W. Beyenbach

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

In the course of electrophysiological studies of Malpighian tubules of the mosquito Aedes aegypti, we have found unusual effects of 2,4-dinitrophenol (DNP) that offer new insights into the electrogenic and conductive properties of the tubule. DNP (10-4 M) depolarized the basolateral membrane voltage from -58.0 to -3.3 mV, and it depolarized the apical membrane voltage from 110.6 to 8.9 mV. In parallel the transepithelial electrical resistance increased from 11.4 to 16.8 kΩ · cm, and the fractional resistance of the apical membrane increased from 0.32 to 0.57. On the assumption that measures of transepithelial resistance in the presence of DNP approach the shunt resistance, the experimental results indicate the following characteristics for the equivalent circuit of the tubule: 1) a shunt resistance that is approximately one-half the transcellular resistance, 2) low and high electromotive forces, respectively, at the basolateral and apical membranes of principal cells, 3) an electrogenic pump at the apical membrane, and 4) a basolateral membrane voltage that is due mostly to the voltage developed by current flow across the basolateral membrane resistance.

Original languageEnglish (US)
Pages (from-to)R609-R614
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume263
Issue number3 32-3
DOIs
StatePublished - Jan 1 1992

Keywords

  • Thevenin equivalent circuits
  • cable analysis
  • electrogenic pump
  • epithelial electrophysiology
  • transcellular and paracellular pathways

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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