Whole-cell potassium currents in fetal rat alveolar type ii epithelial cells cultured on matrigel matrix. Liu, Shenwei, and Alan J. Mautone. Departments of Physiology, Anesthesiology and Pediatrics, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103
APStracts 2:0184L, 1995.
Patch clamp studies were performed on fetal rat alveolar type II cells isolated at 19 days gestation and cultured on either plastic for 7 days or Matrigel matrix (40-50 [mu]l/cm2) for 10 days. Prior to study cells cultured on Matrigel matrix were dissociated from alveolar-like structures (ALS) with enzymes, replated and washed with cold buffer at a constant flow rate to remove residual gel. This wash significantly improved obtaining of successful seals. Potassium current-voltage relationships and maximum whole-cell K+ conductance (Gmax, normalized to membrane capacitance) were significantly changed with time in cells cultured on plastic, but no significant change occurred in cells cultured on Matrigel matrix. Application of 20 mM tetraethylammonium (TEA), 2 mM 4-aminopyridine (4-AP) and 5 mM BaCl2 significantly inhibited K+ currents, showing differences in channel sensitivity to these agents and a voltage-dependent blockage between culture groups or with time in culture. To conclude, we have developed a new method by which epithelial cells cultured on Matrigel matrix can be successfully studied using patch clamp techniques. Further, these studies show that fetal type II cells have voltage -activated K+ channels, and that channel density and their sensitivity to channel blockers are modulated by the substratum on which the cells are cultured. 

Received 7 June 1995; accepted in final form 26 September 1995.
APS Manuscript Number L181-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95