EFFECTS OF VERAPAMIL ON OVALBUMIN INDUCED CONTRACTION OF SENSITIZED GUINEA PIGS LUNG PARENCHYMAL TISSUES, IN VITRO

Abstract

Calcium ions play an important patho-physiological role in allergic reactions. The release of mediators from mast cells, synthesis of some newly formed chemical mediators, airway smooth muscle contraction and nerve impulse conduction are all dependent on the availability and influx of Ca++ ions. It is therefore likely, that Ca++ antagonist, verapamil may modify the allergic broncho-pulmunary responses.

Investigate the effects of verapamil on ovalbumin induced contractile responses on lung parenchymal tissue strip in vitro. Guinea pigs treated with two high doses of ovalbumin i.e. 5 mg on day 0 and 10mg on day 2, intra-peritoneal. Twenty-one days after sensitization the effect of verapamil on guinea pigs, parenchymal tissue was evaluated by incubation of strip with verapamil for 10 minutes and treated with EC50 ovalbumin.

Verapamil exhibits dose dependent inhibition of ovalbumin-induced contraction with significant effect at concentration 10-9 g/ml.

On the basis of these observations two possible mechanisms for this protective effects were suggested, firstly verapamil may have suppressed mediator release and second verapamil may have inhibited the contractile effect of mediators on parenchymal smooth muscle. It is therefore suggested that verapamil may prove useful in the management of airway hyper-reactivity.