Effects of dexamethasone on L-type calcium currents in the A7r5 smooth muscle-derived cell line.
Patch clamp experiments were used to characterize the effect of dexamethasone on calcium currents in A7r5 cells. Pretreatment for 48 h with 200 nM dexamethasone did not affect the single channel conductance, the voltage dependence of channel opening, or the voltage-dependent inactivation of L-type channels. However, dexamethasone caused an approximately 2-fold increase in the amplitude of L-type calcium currents in 5 out of 9 experiments, suggesting an increase in the number of active channels. The effect of dexamethasone appeared to be greatest on batches of cells with low control current density. The amplitude of T-type calcium current was not affected by dexamethasone.
Obejero-Paz
C A
CA
Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106.
Lakshmanan
M
M
Jones
S W
SW
Scarpa
A
A
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology*; D004594:Electrophysiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats
D015220:Calcium Channels; D003907:Dexamethasone