Hypothesis 1: Parthenolide does not directly agonize or antagonize ADORA2A; instead it lowers inflammatory adenosine tone in corticostriatal circuits by suppressing NF-kB-driven ectonucleotidase and cytokine programs in astrocytes and microglia. Less extracellular adenosine would reduce tonic ADORA2A signaling and favor D2-linked antidepressant network states. Test: adenosine microdialysis, CD39/CD73 expression, and ADORA2A-cAMP readouts after parthenolide.
Hypothesis 2: Parthenolide covalently perturbs upstream adenosine transport or metabolism, for example ENT1/ENT2 trafficking or adenosine kinase balance, creating a context-specific shift in receptor occupancy that is only visible in stressed brain tissue. Test: transporter uptake assays, adenosine kinase activity, and receptor occupancy competition in striatal membranes.
Hypothesis 3: The compound changes membrane redox and lipid microdomain organization enough to alter ADORA2A receptor coupling efficiency without high-affinity orthosteric binding. This would explain apparently specific downstream signaling with weak direct binding data. Test: BRET-based Gs coupling, nanodomain imaging, and phospho-CREB mapping with and without cholesterol disruption.