Effects of loratadine on cytosolic Ca2+ levels and leukotriene release: novel mechanisms of action independent of the anti-histamine activity.

Article Details

Citation

Letari O, Miozzo A, Folco G, Belloni PA, Sala A, Rovati GE, Nicosia S

Effects of loratadine on cytosolic Ca2+ levels and leukotriene release: novel mechanisms of action independent of the anti-histamine activity.

Eur J Pharmacol. 1994 Feb 15;266(3):219-27.

PubMed ID
8174605 [ View in PubMed
]
Abstract

Loratadine, a non-sedating anti-histamine drug, displays in vitro potential anti-allergic properties not related to its interaction with the histamine H1 receptor. In a search for the mechanisms of these actions, we have found that loratadine induces an elevation of cytosolic calcium ion, [Ca2+]i, in rat peritoneal macrophages or human platelets. The mechanism of this elevation resides in the ability of loratadine to discharge intracellular Ca2+ stores, similarly to thapsigargin. This in turn brings about the inhibition of [Ca2+]i rise induced by physiological activators (platelet activating factor and ADP), as well as by thapsigargin. One of the active metabolites of loratadine, descarbo-ethoxy-loratadine, and another anti-histamine, namely terfenadine, exhibit the same effects. In addition, loratadine partially inhibits antigen-induced leukotriene release from human bronchi, but is unable to inhibit the concomitant contraction. We conclude that loratadine can interfere with the mechanisms controlling Ca2+ release, thus inhibiting the cell activation elicited by various agonists through [Ca2+]i elevation. This might be the mechanism underlying its anti-allergic actions in vitro. Furthermore, loratadine might represent an interesting tool in the study of Ca2+ homeostasis.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
DesloratadineHistamine H1 receptorProteinHumans
Yes
Antagonist
Details
LoratadineHistamine H1 receptorProteinHumans
Yes
Antagonist
Details