Syed Saud Hasan, Muhammad Yousuf Salat, Naseer Baloch, Jan Mohammad Sheikh.
Role of calcium channel blocker (Verapamil) in the Ovalbumin sensitized bronchial tissue of guinea pigs, in vitro.
Med Channel Jan ;10(3):62-4.
The degranulation of mast cells and contraction of airway smooth muscle are dependent upon the influx of calcium ions. A calcium channel blocking agent verapamil may modify allergic broncho-constriction at least by interference of these two mechanisms of calcium mobilization. Guinea pigs are sensitize with two closes of ovalbumin i.e 5mg on day 0 and 10mg on day 2 intraperitoneally. After 21 days of sensitization, the bronchial strip is treated with ovalbumin to confirm the sensitization. After calculating the EC50 dose then measure the close response. We examined the effects by adding verapamil in different concentration i.e. (from 10e11 g/ml - 10e9 gm/ml) to the incubation medium for 10 minutes then calculate the ovalbumin EC50, induced response. The effects of EC50 ovalbumin observed with verapamil incubation were significantly different from control (EC50, ovalbumin) and the response was close dependent. Verapamil in concentration 10e9 g/ml caused complete inhibition of antigen induced contraction of sensitized bronchial strip. These results suggest that verapamil, did not prevent allergic broncho-contraction by a direct action on smooth muscle but it was effective by inhibiting the release of mast cell mediators which are responsible for airway smooth muscle contraction.
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