Apigenin acts as a monoamine transporter activator, one of the few chemicals demonstrated to possess this property.  Apigenin is a weak ligand for central benzodiazepine receptors in vitro and exerts anxiolytic and slight sedative effects in an animal model .  Apigenin shows second-order positive modulatory activity at GABA A receptors.   It has also effects on adenosine receptors  and is an acute antagonist at the NMDA receptors ( IC 50 = 10 μM).  In addition, like various other flavonoids, apigenin has been found to possess nanomolar affinity for the opioid receptors (K e = 410 nM, 970 nM, and 410 nM for the μ- , δ- , and κ-opioid receptors , respectively), acting as a non-selective antagonist of all three opioid receptors.