Abstract
Proliferation and differentiation in many cells are linked to specific changes in transmembrane ion fluxes. Previously, we have identified a nonspecific cation channel in keratinocytes, which is permeable to and activated by Ca++. To test whether this cation channel might serve as a pathway for Ca++ entry, we examined the effect of blocking this channel on membrane currents, markers of differentiation, and intracellular Ca++. In patch clamp studies, 10-8 to 10-6 M amiloride decreased the single-channel open probability. The same concentrations of amiloride inhibited the calcium-induced formation of cornified envelopes and activity of transglutaminase in a dose-dependent fashion. Amiloride inhibited the long-term rise of intracellular Ca++ induced by raised extracellular Ca++, without blocking the initial increase of intracellular Ca++. Amiloride at concentrations of 10-7 to 10-3 M did not change the resting intracellular pH of keratinocytes, although concentrations of 10-6 M or greater inhibited the recovery from NH4 +-induced acidification. To test whether the effect of amiloride was toxic, we measured DNA synthesis in the presence or absence of amiloride. DNA synthesis was unchanged, suggesting that amiloride's actions were not due to toxic effects. Although the exact mechanism of amiloride's action remains to be determined, these experiments suggest that this compound may inhibit keratinocyte differentiation by blocking the nonspecific cation channel.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 203-208 |
| Number of pages | 6 |
| Journal | Journal of Investigative Dermatology |
| Volume | 105 |
| Issue number | 2 |
| State | Published - 1995 |
| Externally published | Yes |
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Keywords
- Calcium
- pH
ASJC Scopus subject areas
- Dermatology
Cite this
Amiloride blocks a keratinocyte nonspecific cation channel and inhibits Ca++-induced keratinocyte differentiation. / Mauro, T.; Dixon, D. B.; Hanley, K.; Isseroff, Roslyn Rivkah; Pappone, P. A.
In: Journal of Investigative Dermatology, Vol. 105, No. 2, 1995, p. 203-208.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Amiloride blocks a keratinocyte nonspecific cation channel and inhibits Ca++-induced keratinocyte differentiation
AU - Mauro, T.
AU - Dixon, D. B.
AU - Hanley, K.
AU - Isseroff, Roslyn Rivkah
AU - Pappone, P. A.
PY - 1995
Y1 - 1995
N2 - Proliferation and differentiation in many cells are linked to specific changes in transmembrane ion fluxes. Previously, we have identified a nonspecific cation channel in keratinocytes, which is permeable to and activated by Ca++. To test whether this cation channel might serve as a pathway for Ca++ entry, we examined the effect of blocking this channel on membrane currents, markers of differentiation, and intracellular Ca++. In patch clamp studies, 10-8 to 10-6 M amiloride decreased the single-channel open probability. The same concentrations of amiloride inhibited the calcium-induced formation of cornified envelopes and activity of transglutaminase in a dose-dependent fashion. Amiloride inhibited the long-term rise of intracellular Ca++ induced by raised extracellular Ca++, without blocking the initial increase of intracellular Ca++. Amiloride at concentrations of 10-7 to 10-3 M did not change the resting intracellular pH of keratinocytes, although concentrations of 10-6 M or greater inhibited the recovery from NH4 +-induced acidification. To test whether the effect of amiloride was toxic, we measured DNA synthesis in the presence or absence of amiloride. DNA synthesis was unchanged, suggesting that amiloride's actions were not due to toxic effects. Although the exact mechanism of amiloride's action remains to be determined, these experiments suggest that this compound may inhibit keratinocyte differentiation by blocking the nonspecific cation channel.
AB - Proliferation and differentiation in many cells are linked to specific changes in transmembrane ion fluxes. Previously, we have identified a nonspecific cation channel in keratinocytes, which is permeable to and activated by Ca++. To test whether this cation channel might serve as a pathway for Ca++ entry, we examined the effect of blocking this channel on membrane currents, markers of differentiation, and intracellular Ca++. In patch clamp studies, 10-8 to 10-6 M amiloride decreased the single-channel open probability. The same concentrations of amiloride inhibited the calcium-induced formation of cornified envelopes and activity of transglutaminase in a dose-dependent fashion. Amiloride inhibited the long-term rise of intracellular Ca++ induced by raised extracellular Ca++, without blocking the initial increase of intracellular Ca++. Amiloride at concentrations of 10-7 to 10-3 M did not change the resting intracellular pH of keratinocytes, although concentrations of 10-6 M or greater inhibited the recovery from NH4 +-induced acidification. To test whether the effect of amiloride was toxic, we measured DNA synthesis in the presence or absence of amiloride. DNA synthesis was unchanged, suggesting that amiloride's actions were not due to toxic effects. Although the exact mechanism of amiloride's action remains to be determined, these experiments suggest that this compound may inhibit keratinocyte differentiation by blocking the nonspecific cation channel.
KW - Calcium
KW - pH
UR - http://www.scopus.com/inward/record.url?scp=0029149308&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029149308&partnerID=8YFLogxK
M3 - Article
C2 - 7543548
AN - SCOPUS:0029149308
VL - 105
SP - 203
EP - 208
JO - Journal of Investigative Dermatology
JF - Journal of Investigative Dermatology
SN - 0022-202X
IS - 2
ER -