Effect of fenspiride on pulmonary function in the rat and guinea pig

Role of C-reactive protein in acute lung injury

Excessive inflammation caused by unregulated inflammatory processes can lead to disease. One example of this is seen in acute lung injury in which an individual is unable to regulate an inflammatory response in the lungs, with the net effect of self-induced tissue injury and loss of organ function. The acute-phase reactant, C-reactive protein, inhibits acute lung injury in animal models and, in this regard, acts as a major anti-inflammatory agent. Therefore, understanding the mechanism by which C-reactive protein elicits this inhibitory effect may provide important information about the design of therapeutic agents for the prevention or treatment of inflammation-mediated tissue injury and resultant loss of organ function.

Capsaicin and neurokinin A-induced bronchoconstriction in the anaesthetised guinea-pig: evidence for a direct action of menthol on isolated bronchial smooth muscle

1. For many years menthol has been used in the treatment of respiratory disorders although, a bronchodilator effect of menthol has yet to be described. Using the bronchoconstrictors capsaicin (acting via stimulating the release of neuropeptides from sensory afferents) and neurokinin A (NKA) we have raised airways resistance in the guinea-pig (GP) and studied the effect of menthol on both capsaicin and NKA-induced bronchoconstriction in vivo. In vitro the effect of menthol on acetylcholine (ACh) and KCl precontracted GP bronchi was also studied. 2. GP (n = 13) were anaesthetized (urethane 1.5 g kg-1, i.p.) and a bolus injection of capsaicin (7.5 micrograms ml-1, i.v.) or infusion of NKA (1 microgram min-1, i.v.) was given either in the presence of air (0.81 min-1) or air impregnated with menthol vapour (7.5 micrograms l-1) freely breathed from a tracheal cannula via a T-piece. Airways resistance (Raw) and ventilation were measured throughout. Bronchi of mean internal diameter (1029 + 73.6 microns; n = 24) were removed from GP (n = 16) and mounted in the Cambustion myograph. Bronchial rings were maximally precontracted with 80 mM KCl or 2 mM ACh. Relaxation due to a cumulative dose of menthol (1- 3000 microM) was measured. 3. Menthol produced a significant (P < 0.05) 51.3% reversal of the capsaicin-induced increase in Raw, and also inhibited the significant (P < 0.05) reduction in minute ventilation (Ve) associated with the capsaicin-induced increased in Raw. Menthol also caused a significant (P < 0.05) 41% reversal of the NKA-induced increase in Raw. The NKA-induced decrease in Ve was again significantly (P < 0.05) reversed with menthol inhalation. Menthol caused a significant (P < 0.001) dose-dependent relaxation of KCl and ACh precontracted bronchi. 4. We have shown that menthol attenuates both capsaicin and NKA-induced bronchoconstriction in vivo and relaxes KCl and ACh preconstricted bronchi in vitro. Menthol inhibition of NKA and capsaicin-induced bronchoconstriction could be, in part, explained by a direct action of menthol on bronchial smooth muscle.