Inhaled fluoride, magnesium salt and L-arginine reverse bronchospasma

In vitro studies showed that fluoride and magnesium salts relax bronchial smooth muscle cells. Their combined administration could have potential interest. Magnesium fluoride salt (MgF₂) is nearly insoluble. A soluble derivate can be obtained by introducing L-arginineinine (L-arginine) between the ions. L-arginine, being the substrate leading to the release of NO, might add another relaxing effect to this derivate. Relaxing effects of NaF, MgSO₄, L-arginine, NaF+MgSO₄ and MgF₂+L-arginine given via the inhaled route were studied on rats challenged with acetylmethylcholine (ACMCH) following eight successive doses. Tested salts were given at the fourth dose of ACMCH. Changes in bronchial resistances (R) were measured and compared to results obtained in a control group, receiving ACMCH alone. NaF, MgSO₄, and L-arginine led to significant bronchorelaxing effects (p < 0.05). The association NaF+MgSO₄ gave a greater decrease in bronchial resistance compared to that obtained with each salt (fluoride and magnesium) separately. (MgF₂, 2L-arginine) induced a significant fall in R at the fourth dose of ACMCH just after its inhalation. R values obtained with (MgF₂, 2L-arginine) were significantly lower than L-arginine alone at the sixth dose of ACMCH (p < 0.05). (MgF₂, 2L-arginine) is a triple combination able to induce a significant and constant bronchodilating effect through three different pathways. The effect looked partly additive.