Lymphocyte calcium signaling involves dihydropyridine-sensitive L-type calcium channels: facts and controversies.
Calcium influx into lymphocytes is essential for activation, differentiation, and effector functions. While several channel- and receptor-types contribute to calcium influx, voltage-gated calcium channels (VGCC) mediate a well-characterized calcium influx pathway that is most exclusively identified in excitable cells. The role of L-type VGCCs, which belong to high-voltage activated calcium channels and are defined as dihydropyridine (DHP) receptors in excitable cells, is well documented. Interestingly, while lymphocytes do not range in the excitable cell category, the modulatory role of DHP agonists and antagonists and the identification of L-type VGCC-related molecules in B and T lymphocytes, mainly in Th2 cells, suggest these proteins are involved in the calcium response of these cells. Because the identity and the regulation of DHP receptors/channels in lymphocytes is far from being solved, we will discuss the challenging issues of demonstrating a role of L-type VGCCs in nonexcitable cells and the arguments supporting their role in lymphocytes. We will comment on the limitation of the use of DHP agonists and antagonists to ascertain a specific involvement of L-type VGCCs in lymphocyte calcium signaling. Finally, we will provide new clues on the interest of a potential use of DHP antagonists in Th2-cell-mediated pathology.
Gomes
Bruno
B
INSERM U563, CHU Purpan, IFR 30, Place du Dr Baylac, 31024 Toulouse Cedex 3, France.
Savignac
Magali
M
Moreau
Marc
M
Leclerc
Catherine
C
Lory
Philippe
P
Guery
Jean-Charles
JC
Pelletier
Lucette
L
D020746:Calcium Channels, L-Type / Q000187:drug effects* / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D004095:Dihydropyridines / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006801:Humans; D008214:Lymphocytes / Q000502:physiology*; D008954:Models, Biological
D020746:Calcium Channels, L-Type; D004095:Dihydropyridines