title: Effects of media buffer systems on growth and electrophysiologic characteristics of cultured sweat duct cells.
abstract: Primary cultures of human reabsorptive sweat duct cells were grown in MCDB 170 medium buffered with either HEPES, bicarbonate, or a mixture of HEPES and bicarbonate buffers. Cultures grown in MCDB media containing bicarbonate seemed to differentiate into a multilayered, keratinized epithelium and began senescing after 1 wk in culture. In contrast, cultures grown in media containing HEPES as the only buffer seemed to undergo a selection process, resulting in the outgrowth of cells that did not multilayer or keratinize extensively for up to 3 or 4 wk in culture. Despite marked differences in growth, cells grown in both bicarbonate and HEPES-buffered media retained electrophysiologic characteristics appropriate to the progenitor. Mean resting potentials were -21.8 +/- 0.8 mV (n = 82), -23.3 +/- 1.3 mV (n = 70) and -18.2 +/- 0.8 mV (n = 82) for duct cells grown in HEPES, bicarbonate, and HEPES-bicarbonate media, respectively. Substitution of Cl- with the impermeant anion gluconate in the bathing medium caused membrane potential depolarization in all media, revealing the presence of a Cl- conductance. Administration of the Na+ conductance inhibitor amiloride hyperpolarized the mean resting potential of cells grown in HEPES medium (-6.8 +/- 0.6 mV, n = 68), bicarbonate medium (-6.9 +/- 0.5 mV, n = 60), and HEPES-bicarbonate medium (-5.9 +/- 0.6 mV, n = 69), demonstrating expression of a Na+ conductance. We observed some but minimal variation with age in any of these conditions.
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside 92521.
authors.forename: C L
authors.initials: CL
authors.lastname: Bell
authors.forename: P M
authors.initials: PM
authors.lastname: Quinton
mesh_terms: D000328:Adult; D000584:Amiloride / Q000494:pharmacology; D001639:Bicarbonates; D002021:Buffers; D002455:Cell Division; D002478:Cells, Cultured; D002712:Chlorides / Q000494:pharmacology; D003470:Culture Media; D046508:Culture Techniques / Q000379:methods; D004439:Eccrine Glands / Q000166:cytology* / Q000502:physiology; D004594:Electrophysiology; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008875:Middle Aged; D013997:Time Factors
chemical_list: D001639:Bicarbonates; D002021:Buffers; D002712:Chlorides; D003470:Culture Media; D000584:Amiloride