Effects Of Izp-94005 (Contignasterol) On Antigen-Induced Bronchial Responsiveness In Ovalbumin-Sensitized Guinea-Pigs

1 We have investigated the novel naturally occurring marine compound, IZP-94005 (contignasterol), as a potential anti-asthma agent, using both in vivo and in vitro models of allergen-induced bronchoconstriction and airway smooth muscle contraction.2 Tracheal rings from ovalbumin (OA)-sensitized guinea-pigs were treated with various concentrations of IZP-94005 for 20 min prior to challenge with ovalbumin. IZP-94005 (3-30 mu M) inhibited responses of sensitized tracheal rings stimulated with OA in a concentration-dependent manner, with an IC50 of 10 mu M.3 IZP-94005 (10 mu M) had no effect on carbachol-induced contractions of sensitized guinea-pig tracheal rings, although it did inhibit histamine-induced responses of OA sensitized guinea-pig tracheal rings.4 The effects of IZP-94005 in vivo were examined using OA-sensitized guinea-pigs which were tracheotomized under anaesthesia and placed in a body plethysmograph. Measurements of lung resistance and compliance were performed by isovolumetric analysis of volume and trans-pulmonary pressure.5 IZP-94005 (50 and 200 mu g kg(-1)), by inhalation 20 min Frier to OA challenge caused significant inhibition of the increase in lung resistance induced by OA in sensitized guinea-pigs, compared to vehicle-treated animals. Nedocromil sodium (20 mg kg(-1)), with a similar protocol, also inhibited OA-induced responses in this model.6 We therefore suggest that IZP-94005 is a good candidate for further investigation as a possible antiasthma agent.