Clemastine (CLE), an H1R antagonist widely used for the treatment of allergic rhinitis, has recently been investigated for its positive modulatory effects on P2X7, a receptor for extracellular ATP (eATP) involved in the regulation of inflammation, immune responses, and the composition of the tumor microenvironment (TME). Here, we further examined the effects of CLE on P2X7-mediated responses to clarify the pharmacological sign...

ATP is a ubiquitous extracellular messenger released in a wide number of pathophysiological conditions. ATP is known to be present in minute amounts in the extracellular space in healthy tissues and in the blood, and to modulate a multiplicity of cell responses. Cell culture systems are widely used to explore purinergic signaling. We show here that currently used fetal bovine sera contain ATP in the 300–1300 pmol/L range. Seru...