TY - JOUR
T1 - Menthol increases human glioblastoma intracellular Ca2+, BK channel activity and cell migration
AU - Wondergem, Robert
AU - Bartley, Jeremy W.
N1 - Funding Information:
JWB was supported by a student summer research fellowship from the Department of Physiology at ETSU.
PY - 2009
Y1 - 2009
N2 - This study examined the effect of menthol, an agonist for transient receptor potential melastatin 8 (TRPM8) ion channels, to increase intracellular Ca2+ concentration, [Ca2+]i, in human glioblastoma cells (DBTRG cells), which resulted in activation of the large-conductance Ca2+-activated K+ membrane ion channels (BK channels). Voltage ramps applied over 300 ms from -100 to 100 mV resulted in membrane currents with marked inwardly- and outwardly-rectifying components. Paxilline (2 M) abolished the outwardly-rectifying current. Outwardly-rectifying on-cell patch currents were increased markedly by menthol (100 M) added to the bath. The estimated on-cell conductance of these channels was 253 pS. Kinetic analysis showed that added menthol increased channel open probability and mean open frequency after 5 min. In a similar time course menthol increased [Ca 2+]i, and this increase was abolished either by added paxilline, tetraethylammonium ion or by Ca2+-free external solution. Finally, menthol stimulated the rate of DBTRG cell migration into scratch wounds made in confluent cells, and this also was inhibited by paxilline or by tetraethylammonium ion. We conclude that menthol, a TRPM8 agonist, increases DBTRG cell [Ca2+]ithat in turn activates membrane BK ion channels. Inhibition of BK channels by paxilline reverses menthol-stimulated increase of [Ca2+]iand of cell migration. Thus, BK channels function to maintain elevations in [Ca2+]ineeded to sustain increases in DBTRG cell migration.
AB - This study examined the effect of menthol, an agonist for transient receptor potential melastatin 8 (TRPM8) ion channels, to increase intracellular Ca2+ concentration, [Ca2+]i, in human glioblastoma cells (DBTRG cells), which resulted in activation of the large-conductance Ca2+-activated K+ membrane ion channels (BK channels). Voltage ramps applied over 300 ms from -100 to 100 mV resulted in membrane currents with marked inwardly- and outwardly-rectifying components. Paxilline (2 M) abolished the outwardly-rectifying current. Outwardly-rectifying on-cell patch currents were increased markedly by menthol (100 M) added to the bath. The estimated on-cell conductance of these channels was 253 pS. Kinetic analysis showed that added menthol increased channel open probability and mean open frequency after 5 min. In a similar time course menthol increased [Ca 2+]i, and this increase was abolished either by added paxilline, tetraethylammonium ion or by Ca2+-free external solution. Finally, menthol stimulated the rate of DBTRG cell migration into scratch wounds made in confluent cells, and this also was inhibited by paxilline or by tetraethylammonium ion. We conclude that menthol, a TRPM8 agonist, increases DBTRG cell [Ca2+]ithat in turn activates membrane BK ion channels. Inhibition of BK channels by paxilline reverses menthol-stimulated increase of [Ca2+]iand of cell migration. Thus, BK channels function to maintain elevations in [Ca2+]ineeded to sustain increases in DBTRG cell migration.
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U2 - 10.1186/1423-0127-16-90
DO - 10.1186/1423-0127-16-90
M3 - Article
C2 - 19778436
AN - SCOPUS:70350638630
SN - 1021-7770
VL - 16
JO - Journal of biomedical science
JF - Journal of biomedical science
IS - 1
M1 - 90
ER -