Epidermal growth factor regulation in adult rat alveolar type II cells of amiloride-sensitive cation channels

Using the patch-clamp technique, we studied the effects of epidermal growth factor (EGF) on whole cell and single channel currents in adult rat alveolar epithelial type II cells in primary culture in the presence or absence of EGF for 48 h. In symmetrical sodium isethionate solutions, EGF exposure caused a significant increase in the type II cell whole cell conductance. Amiloride (10 microM) produced approximately 20-30% inhibition of the whole cell conductance in both the presence and absence of EGF, such that EGF caused the magnitude of the amiloride-sensitive component to more than double. Northern analysis showed that alpha-, beta- and gamma-subunits of rat epithelial Na(+) channel (rENaC) steady-state mRNA levels were all significantly decreased by EGF. At the single channel level, all active inside-out patches demonstrated only 25-pS channels that were amiloride sensitive and relatively nonselective for cations (P(Na(+))/P(K(+)) approximately 1.0:0.48). Although the biophysical characteristics (conductance, open-state probability, and selectivity) of the channels from EGF-treated and untreated cells were essentially identical, channel density was increased by EGF; the modal channel per patch was increased from 1 to 2. These findings indicate that EGF increases expression of nonselective, amiloride-sensitive cation channels in adult alveolar epithelial type II cells. The contribution of rENaC to the total EGF-dependent cation current under these conditions is quantitatively less important than that of the nonselective cation channels in these cells.

Medienart:

E-Artikel

Erscheinungsjahr:

1999

Erschienen:

1999

Enthalten in:

Zur Gesamtaufnahme - volume:277

Enthalten in:

The American journal of physiology - 277(1999), 6 vom: 17. Dez., Seite C1058-65

Sprache:

Englisch

Beteiligte Personen:

Kemp, P J [VerfasserIn]
Borok, Z [VerfasserIn]
Kim, K J [VerfasserIn]
Lubman, R L [VerfasserIn]
Danto, S I [VerfasserIn]
Crandall, E D [VerfasserIn]

Links:

Volltext

Themen:

62229-50-9
7DZO8EB0Z3
9NEZ333N27
Amiloride
Diuretics
Epidermal Growth Factor
Epithelial Sodium Channels
Journal Article
RNA, Messenger
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Sodium
Sodium Channels

Anmerkungen:

Date Completed 20.01.2000

Date Revised 20.09.2018

published: Print

Citation Status MEDLINE

doi:

10.1152/ajpcell.1999.277.6.C1058

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM105305464