a popped is a mean of inhibitor
knock is bump. anticatalyst is inhibitor. defenestration is ejection. slap is bump. pde2_inhibitor is pde_selective_inhibitor. pde4_inhibitor is pde_selective_inhibitor. pde4_inhibitor is not pde_selective_inhibitor. inhibitor is substance. pde1_selective_inhibitor is pde_selective_inhibitor. pde5_selective_inhibitor is pde_selective_inhibitor.