Effects of magnesium sulfate on airway smooth muscle contraction in rats

<p><strong>Aim <br /></strong>To investigate the effect of magnesium sulfate (MgSO4) at different doses on isolated tracheal smooth muscle contraction in rats induced by different mechanisms.<br /><strong>Methods<br /></strong> Twelve rats’ tracheas were placed into organ bath. Consecutively, acetylcholine (10−6,10−5,10−4 M), histamine<br />(10−8,10−5,10−3 M) and KCl (30,60 mM) solutions was administered for contractions. MgSO4  from 10−4 to 10−1 M concentrations were subsequently administered after each constrictive agent and relaxation degrees were recorded.<br /><strong>Results<br /></strong> In the acetylcholine and KCl groups, dose dependent strong contractions were observed, but not in the histamine group<br />and that group was excluded. Significant relaxation occurred with gradually increasing doses of MgSO4. In the high dose KCl group, a slight increase in contractions after the administration of 10−4 and 10−3 M MgSO4 was recorded.<br /><strong>Conclusion<br /></strong> We suggest that MgSO4 is effective in relaxing airway smooth muscle contractions caused by different factors; however,<br />it must be considered that low doses of MgSO4 may only lead to a slight increase in contractions.</p>