Fig. 10: Conformational changes of IP-HD during P2X3 receptor channel gating, and schematic diagram of the mechanism of inhibition by quercetin and PSFL2915.
From: Chronic cough relief by allosteric modulation of P2X3 without taste disturbance

Tightening of IP-HD is essential for P2X3 receptor activation, and quercetin from natural products inhibits P2X3 receptor activation by blocking the tightening of IP-HD. This likely underlies the main mechanism of quercetin and PSFL2915 in cough relief.