Limits...
Pharmacological evidences for the stimulation of calcium-sensing receptors by nifedipine in gingival fibroblasts.

Hattori T, Ara T, Fujinami Y - J Pharmacol Pharmacother (2011)

Bottom Line: This confirmed the pathway components mediating Ca(2+) responses to a known agonist of the CaSR.Calphostin C (a PKC inhibitor) and TMB-8 (an inhibitor of Ca(2+) release from stores) also inhibited the nifedipine-induced [Ca(2+)] i elevation.These findings suggest that CaSRs are involved in the nifedipine-induced [Ca(2+)] i elevation in gingival fibroblasts.

View Article: PubMed Central - PubMed

Affiliation: Department of Dental Pharmacology, Matsumoto Dental University, Shiojiri 399-0781, Japan.

ABSTRACT

Objective: To investigate pharmacologically whether CaSRs are involved in the Ca(2+) antagonist-induced [Ca(2+)]i elevation in gingival fibroblasts.

Materials and methods: Gin-1 cells, normal human gingival fibroblasts, were used as the material. The [Ca(2+)] i was measured with fura-2/AM, a Ca(2+)-sensitive fluorescent dye.

Results: At first, we confirmed the existence of CaSRs in these cells by showing that [Ca(2+)] i was elevated by high concentrations of extracellular Ca(2+) and by prototypic agonists of the CaSR such as gentamicin. The action of gentamicin was antagonized by inhibitors of phospholipase C (PLC), inositol trisphosphate (IP(3)) receptors, NSCCs, and, importantly, by the CaSR antagonist, NPS2390. Furthermore, the action of gentamicin was potentiated by activators of PLC and protein kinase C (PKC). This confirmed the pathway components mediating Ca(2+) responses to a known agonist of the CaSR. We then investigated whether nifedipine (an L-type Ca(2+) channel blocker) stimulates CaSRs to elevate [Ca(2+)] i via a similar mechanism. Nifedipine Ca(2+) responses were dose-dependently blocked by NPS2390 and by the same inhibitors of PLC, IP(3) receptors, and NSCCs that disrupted the action of gentamicin. Calphostin C (a PKC inhibitor) and TMB-8 (an inhibitor of Ca(2+) release from stores) also inhibited the nifedipine-induced [Ca(2+)] i elevation.

Conclusion: These findings suggest that CaSRs are involved in the nifedipine-induced [Ca(2+)] i elevation in gingival fibroblasts.

No MeSH data available.


Related in: MedlinePlus

Effects of the high extracellular Ca2+ concentration ([Ca2+]o) on the [Ca2+]i of gingival fibroblasts. Application of Ca2+ (2–10 mM) in the perfusion buffer concentration dependently elevated the [Ca2+]i. The upper trace shows a time course of the [Ca2+]i. Data are mean ± SEM, N = 20. ***P < 0.005, ****P < 0.001 compare to corresponding pretreated values
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3117567&req=5

Figure 0001: Effects of the high extracellular Ca2+ concentration ([Ca2+]o) on the [Ca2+]i of gingival fibroblasts. Application of Ca2+ (2–10 mM) in the perfusion buffer concentration dependently elevated the [Ca2+]i. The upper trace shows a time course of the [Ca2+]i. Data are mean ± SEM, N = 20. ***P < 0.005, ****P < 0.001 compare to corresponding pretreated values

Mentions: Though the study was initially planned to carry out the CaSRs expressed in the Gin-1 cells used in this experiment, later the protocol was modified to evaluate [Ca2+]i changes following the administration of a range of concentrations (2–10 mM) of extracellular Ca2+. Figure 1 illustrates that extracellular Ca2+ dose-dependently elevates [Ca2+]i in these cells.


Pharmacological evidences for the stimulation of calcium-sensing receptors by nifedipine in gingival fibroblasts.

Hattori T, Ara T, Fujinami Y - J Pharmacol Pharmacother (2011)

Effects of the high extracellular Ca2+ concentration ([Ca2+]o) on the [Ca2+]i of gingival fibroblasts. Application of Ca2+ (2–10 mM) in the perfusion buffer concentration dependently elevated the [Ca2+]i. The upper trace shows a time course of the [Ca2+]i. Data are mean ± SEM, N = 20. ***P < 0.005, ****P < 0.001 compare to corresponding pretreated values
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117567&req=5

Figure 0001: Effects of the high extracellular Ca2+ concentration ([Ca2+]o) on the [Ca2+]i of gingival fibroblasts. Application of Ca2+ (2–10 mM) in the perfusion buffer concentration dependently elevated the [Ca2+]i. The upper trace shows a time course of the [Ca2+]i. Data are mean ± SEM, N = 20. ***P < 0.005, ****P < 0.001 compare to corresponding pretreated values
Mentions: Though the study was initially planned to carry out the CaSRs expressed in the Gin-1 cells used in this experiment, later the protocol was modified to evaluate [Ca2+]i changes following the administration of a range of concentrations (2–10 mM) of extracellular Ca2+. Figure 1 illustrates that extracellular Ca2+ dose-dependently elevates [Ca2+]i in these cells.

Bottom Line: This confirmed the pathway components mediating Ca(2+) responses to a known agonist of the CaSR.Calphostin C (a PKC inhibitor) and TMB-8 (an inhibitor of Ca(2+) release from stores) also inhibited the nifedipine-induced [Ca(2+)] i elevation.These findings suggest that CaSRs are involved in the nifedipine-induced [Ca(2+)] i elevation in gingival fibroblasts.

View Article: PubMed Central - PubMed

Affiliation: Department of Dental Pharmacology, Matsumoto Dental University, Shiojiri 399-0781, Japan.

ABSTRACT

Objective: To investigate pharmacologically whether CaSRs are involved in the Ca(2+) antagonist-induced [Ca(2+)]i elevation in gingival fibroblasts.

Materials and methods: Gin-1 cells, normal human gingival fibroblasts, were used as the material. The [Ca(2+)] i was measured with fura-2/AM, a Ca(2+)-sensitive fluorescent dye.

Results: At first, we confirmed the existence of CaSRs in these cells by showing that [Ca(2+)] i was elevated by high concentrations of extracellular Ca(2+) and by prototypic agonists of the CaSR such as gentamicin. The action of gentamicin was antagonized by inhibitors of phospholipase C (PLC), inositol trisphosphate (IP(3)) receptors, NSCCs, and, importantly, by the CaSR antagonist, NPS2390. Furthermore, the action of gentamicin was potentiated by activators of PLC and protein kinase C (PKC). This confirmed the pathway components mediating Ca(2+) responses to a known agonist of the CaSR. We then investigated whether nifedipine (an L-type Ca(2+) channel blocker) stimulates CaSRs to elevate [Ca(2+)] i via a similar mechanism. Nifedipine Ca(2+) responses were dose-dependently blocked by NPS2390 and by the same inhibitors of PLC, IP(3) receptors, and NSCCs that disrupted the action of gentamicin. Calphostin C (a PKC inhibitor) and TMB-8 (an inhibitor of Ca(2+) release from stores) also inhibited the nifedipine-induced [Ca(2+)] i elevation.

Conclusion: These findings suggest that CaSRs are involved in the nifedipine-induced [Ca(2+)] i elevation in gingival fibroblasts.

No MeSH data available.


Related in: MedlinePlus