Anxiolytic effect of chronic intake of supplemental magnesium chloride in rat.

Evidence suggest that magnesium dietary supplementation has several health benefits including lowering blood pressure, reducing insulin resistance, and improving symptoms of depression, anxiety, and migraine. Here, we aimed to study the effect of chronic magnesium supplementation on anxiety-like behavior in rats by supplementing with magnesium their drinking water for 30 days. Anxiety-like behavior was induced by subcutaneous injection of veratrin 30 min before performing elevated plus maze and open field tests to measure anxiety levels and locomotion, respectively. We quantify the concentration of magnesium in plasma and cerebrospinal fluid. We used diazepam to compare the efficacy of magnesium supplementation as an anxiolytic agent. Our results show that rats supplemented with magnesium had a statistically significant decrease in anxiety levels with not effects on locomotion and a statistically significant increase in concentration of magnesium in plasma and cerebrospinal fluid. However, the anxiolytic effect of magnesium supplementation washes-out in 12 days. We discuss the advantages of using supplemental magnesium as anxiolytic.

Effects of chronic administration of tryptophan with or without concomitant fluoxetine in depression-related and anxiety-like behaviors on adult rat.

Depression and anxiety play an important role in decreasing quality of life worldwide. Since tryptophan is a serotonin precursor and low levels of serotonin seems to be related to depression, the effect of oral tryptophan has been investigated for possible potentiation of the action of antidepressant drugs. We investigated the effects of chronically administered tryptophan (50mg/kg/day, p.o.) with or without concomitant fluoxetine (10mg/kg/day, s.c.) on adult rats regarding depression-related and anxiety-like behaviors. Tryptophan levels in cerebrospinal fluid (CSF) were measured 4h after a single administration of daily dosages of chronic treatments. We found that tryptophan increased depressive-related behavior, but did not alter anxiety-like behavior. However, fluoxetine decreased depression-related behavior and was anxiogenic. Tryptophan with concomitant fluoxetine did not alter anxiety-like behavior. Moreover, our data suggests that the antidepressant effect of fluoxetine was not enhanced by concomitant administration of tryptophan, which could be associated with increased levels of tryptophan in CSF. Further investigations are needed to elucidate the related mechanisms.