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Stimulant-like effects of magnesium on aggression in mice
Abstract:
The effects of magnesium excesses resulting from daily injections of magnesium chloride (MgCl2) were examined on offensive behavior in a resident-intruder situation. Male mice tested 5 min post-injection of 15 mg/kg or 30 mg/kg exhibited a significantly greater number of attacks and threats than saline controls; while in mice injected with 125 mg/kg threat and attack behaviors were decreased. No tolerance developed to this decrease which persisted throughout the 15 day injection period. Tolerance to the aggression enhancing effects developed in the 30 mg/kg group which returned to normal by Day 4 and in the 15 mg/kg group which returned to normal by Day 15. Two weeks following the last injection, all groups performed equally. When mice were tested prior to daily injections on Days 4, 8, and 15 in a second experiment, there were no MgCl2 dose differences in threat or attack behavior, thus there was no cumulative effect of MgCl2 on behavior. These data and our previous data showing that MgCl2 deficiencies reduce offensive aggression suggest an inverted U-shape function to magnesium's influence on behavior. Since aggression has been linked to the neurotransmitters dopamine, norepinephrine, and serotonin, and magnesium has been shown to be an important cofactor in the activity of these neurotransmitters, it is possible that the effects seen here are related to changes in one or more of these systems.
Insights
Magnesium chloride (MgCl2) injections affected mouse aggression, with moderate doses increasing attacks and high doses decreasing them. These effects suggest an inverted U-shape function for magnesium
Area of Science:
- Neuroscience
- Behavioral Science
- Pharmacology
Background:
- Magnesium is an essential mineral involved in numerous physiological processes.
- Previous research indicates magnesium deficiencies reduce offensive aggression.
- The impact of magnesium excess on behavior, particularly aggression, is less understood.
Purpose of the Study:
- To investigate the effects of acute and chronic magnesium chloride (MgCl2) excess on offensive aggression in male mice.
- To determine if tolerance develops to the behavioral effects of MgCl2.
- To explore the dose-dependent relationship between MgCl2 administration and aggressive behavior.
Main Methods:
- Male mice were subjected to resident-intruder tests following daily injections of varying MgCl2 doses (15, 30, or 125 mg/kg) or saline.
- Offensive behaviors (attacks, threats) were quantified.
- Tolerance and cumulative effects were assessed through repeated testing over 15 days and testing prior to injections.
Main Results:
- Intermediate MgCl2 doses (15 and 30 mg/kg) initially increased attacks and threats.
- A high MgCl2 dose (125 mg/kg) decreased these behaviors without tolerance development.
- Tolerance to the aggression-enhancing effects occurred in the 15 and 30 mg/kg groups over time; no cumulative effects were observed.
Conclusions:
- Magnesium's influence on offensive aggression follows an inverted U-shape function, with both deficiency and excess impacting behavior.
- The observed effects may be linked to magnesium's role as a cofactor in neurotransmitter systems (dopamine, norepinephrine, serotonin).
- MgCl2 administration can modulate aggressive behaviors in a dose- and time-dependent manner.