Angiotensin II regulates endothelial cell migration through calcium influx via T-type calcium channel in human umbilical vein endothelial cells.
OBJECTIVE
The T-type calcium channel is expressed in vascular endothelial cells, but its role in endothelial cell function is yet to be elucidated. We analysed the endothelial functional role of T-type calcium channel-dependent calcium under angiotensin II (Ang II) stimulation.


METHODS
Human umbilical vein endothelial cells were co-incubated with hormone at 10(-7) m and either Efonidipine 10(-5) m or Verapamil 10(-5) m or Mibefradil 10(-5) m or Wortmannin 10(-6) m. The contribution of Ang II receptors was evaluated using PD123319 10(-7) m and ZD 7155 10(-7) m. The calcium ion concentration was observed using Fluo-3 acetossimetil ester. The cells were observed after 3, 6, 9 and 12 h.


RESULTS
The microfluorescence method points out that Ang II induces intracellular calcium modulation in time by distinct mechanisms. AT2 receptor blockade is necessary to observe significant increase in [Ca(2+)](i) levels. Pre-treatment with Mibefradil abolishes Ang II -induced cell migration.


CONCLUSIONS
Our data show that Ang II, via AT1 receptor, modulates calcium concentration involving T-type calcium channel and L-type calcium channel but only the calcium influx via T-type calcium channels regulates endothelial cell migration which is essential for angiogenesis.
Martini
A
A
Department of Cell Biology, Calabria University, Rende, Italy. amartini@unical.it <amartini@unical.it>
Bruno
R
R
Mazzulla
S
S
Nocita
A
A
Martino
G
G
D000804:Angiotensin II / Q000494:pharmacology / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020747:Calcium Channels, T-Type / Q000502:physiology*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D014471:Umbilical Veins / Q000166:cytology*
D002121:Calcium Channel Blockers; D020747:Calcium Channels, T-Type; D000804:Angiotensin II; D002118:Calcium