Sildenafil decreases rat tracheal hyperresponsiveness to carbachol and changes canonical transient receptor potential gene expression after antigen challenge

Inhibitory effects of a standardized extract of Justicia pectoralis in an experimental rat model of airway hyper-responsiveness

“…While gene expression of TRPC1 and TRPC6 decreased, TRPC5 increased and TRPC4 was refractory to the antigen challenge. Upregulation of TRPC1 expression was reported in rat trachea and proliferating airway smooth muscle cells, while TRPC1 downregulation diminished store‐depletion‐induced Ca 2+ influx and airway hyper‐responsiveness in the presence of inflammatory mediators . In mice challenged with OVA, downregulation of TRPC6 resulted in increased agonist‐induced contractility of tracheal rings, findings in line with the present results obtained with rat airways.…”

Ligustrazine Inhibits Lung Phosphodiesterase Activity in a Rat Model of Allergic Asthma

“…In rabbits, ligustrazine can induce corpus cavernosum smooth muscle relaxation via a mechanism independent of nitric oxide and the endothelium, but that is mediated by cAMP phosphodiesterase inhibition of cGMP phosphodiesterase [ 36 ]. This is similar to the PDE5 inhibitor sildenafil, which is effective for treating asthma and COPD (chronic obstructive pulmonary disease) in addition to being used as an erectile dysfunction drug [ 42 , 43 ]. As it is associated with many side effects, however, the use of sildenafil remains controversial for the treatment of lung diseases [ 44 ].…”

Pharmacology and Therapeutics of Bronchodilators

“…This drug has already successfully undergone a number of phase 2 clinical trials in patients with either COPD or asthma (http://www.veronapharma.com). There are also some recent pilot data showing that PDE5 inhibitors such as sildenafil can have bronchodilator activities (Sousa et al, 2011).…”