الفهرس 
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Abstract
The results of the present study demonstrate that sodium fluoride (NaF) produced marked concentration-dependent contraction in the isolated pulmonary arterial rings and tracheal strips of rats. Preincubation with chlorpheniramine, indomethacin, NDGA and L-NAME did not alter the NaP induced contraction of the isolated pulmonary arterial rings and tracheal strips of rats. Phentolamine did not change the contractile effect of NaF on the isolated pulmonary arterial rings. The NaF-induced contraction of isolated tracheal strips was not altered by pretreatment with atropine. On the other hand, nifedipine and melatonin totally abolished response to the small concentration of NaF and caused significant decrease in NaF-induced contraction of the pulmonary arterial rings and tracheal strips at the other concentrations.
Aminophylline produced significant decrease in the NaF -induced contraction of the isolated pulmonary arterial rings only at the small concentrations. However, aminophylline did not produce any significant change in NaF-induced contraction of the tracheal strips of rats.
Therefore, the contractile effect of NaF on the pulmonary arterial rings and tracheal strips is dependent on the extracellular calcium and could be mediated via free radicals. This study also suggests a role of adenosine receptor m mediating the contraction of pulmonary arterial rings.