Abstract
The effects of diazepam on voltage-gated Ca channels were studied in PC12 pheochromocytoma cells using whole-cell voltage-clamp techniques. An inward current activated by a depolarizing voltage step to +10 mV from a holding potential of -60 mV in 10.8 mM Ba was larger than thatactivated in 10.8 mM Ca. The Ba current was completely blocked by a low concentration of Cd (30 μM) and was also sensitive to nicardipine (100 nM to 10 μM). Diazepam (1-100 μM) inhibited the Ba current in a concentration-dependent manner. Neither diazepam nor nicardipine affected the current-voltage relationship or the dependence on holding potentials of the Ba current. Both slightly accelerated the inactivation time course of the Ba current. When diazepam was applied to the cells in combination with nicardipine, the observed inhibition agreed with a value predicted assuming independent blockade by diazepam and by nicardipine. These results suggest that diazepam inhibits Ca channels in a manner similar to nicardipine, but that the binding sites for diazepam are different from those for nicardipine.
| Original language | English |
|---|---|
| Pages (from-to) | 44-50 |
| Number of pages | 7 |
| Journal | Brain Research |
| Volume | 553 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jul 5 1991 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Neuroscience(all)
- Molecular Biology
- Clinical Neurology
- Developmental Biology
Cite this
Inhibition of Ca-channels by diazepam compared with that by nicardipine in pheochromocytoma PC12 cells. / Nakazawa, Ken; Inoue, Kazuhide; Ohara-Imaizumi, Mica; Fujimori, Kannosuke; Takanaka, Akira.
In: Brain Research, Vol. 553, No. 1, 05.07.1991, p. 44-50.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Inhibition of Ca-channels by diazepam compared with that by nicardipine in pheochromocytoma PC12 cells
AU - Nakazawa, Ken
AU - Inoue, Kazuhide
AU - Ohara-Imaizumi, Mica
AU - Fujimori, Kannosuke
AU - Takanaka, Akira
PY - 1991/7/5
Y1 - 1991/7/5
N2 - The effects of diazepam on voltage-gated Ca channels were studied in PC12 pheochromocytoma cells using whole-cell voltage-clamp techniques. An inward current activated by a depolarizing voltage step to +10 mV from a holding potential of -60 mV in 10.8 mM Ba was larger than thatactivated in 10.8 mM Ca. The Ba current was completely blocked by a low concentration of Cd (30 μM) and was also sensitive to nicardipine (100 nM to 10 μM). Diazepam (1-100 μM) inhibited the Ba current in a concentration-dependent manner. Neither diazepam nor nicardipine affected the current-voltage relationship or the dependence on holding potentials of the Ba current. Both slightly accelerated the inactivation time course of the Ba current. When diazepam was applied to the cells in combination with nicardipine, the observed inhibition agreed with a value predicted assuming independent blockade by diazepam and by nicardipine. These results suggest that diazepam inhibits Ca channels in a manner similar to nicardipine, but that the binding sites for diazepam are different from those for nicardipine.
AB - The effects of diazepam on voltage-gated Ca channels were studied in PC12 pheochromocytoma cells using whole-cell voltage-clamp techniques. An inward current activated by a depolarizing voltage step to +10 mV from a holding potential of -60 mV in 10.8 mM Ba was larger than thatactivated in 10.8 mM Ca. The Ba current was completely blocked by a low concentration of Cd (30 μM) and was also sensitive to nicardipine (100 nM to 10 μM). Diazepam (1-100 μM) inhibited the Ba current in a concentration-dependent manner. Neither diazepam nor nicardipine affected the current-voltage relationship or the dependence on holding potentials of the Ba current. Both slightly accelerated the inactivation time course of the Ba current. When diazepam was applied to the cells in combination with nicardipine, the observed inhibition agreed with a value predicted assuming independent blockade by diazepam and by nicardipine. These results suggest that diazepam inhibits Ca channels in a manner similar to nicardipine, but that the binding sites for diazepam are different from those for nicardipine.
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U2 - 10.1016/0006-8993(91)90228-N
DO - 10.1016/0006-8993(91)90228-N
M3 - Article
C2 - 1718541
AN - SCOPUS:0025820280
VL - 553
SP - 44
EP - 50
JO - Brain Research
JF - Brain Research
SN - 0006-8993
IS - 1
ER -