Stimulant-like effects of magnesium on aggression in mice

Magnesium intake was inversely associated with hostility among American young adults

Hostility is a complex personality trait associated with many cardiovascular risk factor phenotypes. Although magnesium intake has been related to mood and cardio-metabolic disease, its relation with hostility remains unclear. We hypothesize that high total magnesium intake is associated with lower levels of hostility because of its putative antidepressant mechanisms. To test the hypothesis, we prospectively analyzed data in 4,716 young adults aged 18-30 years at baseline (1985-1986) from four U.S. cities over five years of follow-up using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Magnesium intake was estimated from a dietary history questionnaire plus supplements at baseline. Levels of hostility were assessed using the Cook-Medley scale at baseline and year 5 (1990-1991). Generalized estimating equations were applied to estimate the association of magnesium intake with hostility as repeated measures at the two time-points (baseline and year 5). General linear model was used to determine the association between magnesium intake and change in hostility over 5 years. After adjustment for socio-demographic and major lifestyle factors, a significant inverse association was observed between magnesium intake and hostility level over 5 years of follow-up. Beta coefficients (95% CI) across higher quintiles of magnesium intake were 0 (reference), -1.28 (-1.92, -0.65), -1.45 (-2.09, -0.81), -1.41 (-2.08, -0.75) and -2.16 (-2.85, -1.47), respectively (Plinear-trend<.01). The inverse association was independent of socio-demographic and major lifestyle factors, supplement use, and depression status at year 5. This prospective study provides evidence that in young adults, high magnesium intake was inversely associated with hostility level independent of socio-demographic and major lifestyle factors.

Iron, Magnesium, Vitamin D, and Zinc Deficiencies in Children Presenting with Symptoms of Attention-Deficit/Hyperactivity Disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder increasing in prevalence. Although there is limited evidence to support treating ADHD with mineral/vitamin supplements, research does exist showing that patients with ADHD may have reduced levels of vitamin D, zinc, ferritin, and magnesium. These nutrients have important roles in neurologic function, including involvement in neurotransmitter synthesis. The aim of this paper is to discuss the role of each of these nutrients in the brain, the possible altered levels of these nutrients in patients with ADHD, possible reasons for a differential level in children with ADHD, and safety and effect of supplementation. With this knowledge, clinicians may choose in certain patients at high risk of deficiency, to screen for possible deficiencies of magnesium, vitamin D, zinc, and iron by checking RBC-magnesium, 25-OH vitamin D, serum/plasma zinc, and ferritin. Although children with ADHD may be more likely to have lower levels of vitamin D, zinc, magnesium, and iron, it cannot be stated that these lower levels caused ADHD. However, supplementing areas of deficiency may be a safe and justified intervention.

The influence of a magnesium-rich marine extract on behaviour, salivary cortisol levels and skin lesions in growing pigs

Growing pigs can display undesirable behaviours, reflecting or causing poor welfare. Addition of magnesium (Mg) to the diet could reduce these, as Mg supplementation has been associated with improved coping ability in response to stress. This study examined the effect of supplementation with a Mg-rich marine extract-based product (Supplement) on the behaviour, skin and tail lesion scores and salivary cortisol concentrations of growing pigs. At weaning (28 days), 448 piglets were assigned to either Control or Supplement (0.05%) diets in single-sex groups of 14. Four weeks later (c. 17 kg), pigs were blocked according to weight and back test scores. Seven piglets from each pen were mixed with seven from another pen of the same sex and dietary treatment to yield the following groups: control male, Supplement male, control female and Supplement female (n = 4 of each). This marked the start of the 9-week experimental period. Instances of the following behaviours were recorded in each pen for 8 × 2 min periods 1 day/week: aggression (fight, head-knock and bite); harmful (tail-in-mouth, ear-chewing and belly-nosing); and sexual/mounting behaviour. Four focal pigs were selected from each pen, and their behaviour was continuously recorded for 2 × 5 min periods on the same day. Saliva was collected once per week at 1000 h by allowing pigs to chew on a cotton bud for c. 1 min. Salivary cortisol was analysed in duplicate by an enzyme immunoassay. Skin and tail lesions were scored according to severity 1 day/week. There were fewer aggressive incidents in Supplement pens (P < 0.01), and mounting behaviour (performed only by males) was almost three times lower in Supplement than in control pens (P < 0.01). However, there was no effect of Supplement on the incidence of each of the harmful behaviours. Behaviour of the focal pigs showed no treatment effect on the duration or incidence of aggressive behaviour. However, Supplement pigs spent less time performing harmful behaviours compared with control pigs (P < 0.001). Supplement had no effect on the occurrence or severity of tail-biting outbreaks or on tail lesion scores. However, Supplement females had lower skin lesion scores, in particular in the ears and shoulders (P < 0.01). Finally, Supplement pigs had lower salivary cortisol concentrations (P < 0.01). Mounting is a major welfare concern in uncastrated pigs, and therefore this represents an important welfare benefit of Supplement. Reduced salivary cortisol, in conjunction with reduced skin lesion scores in supplemented females, suggests that addition of a Mg-rich marine extract improved pig welfare in this system.

Complementary and alternative therapies for children and adolescents with ADHD

PURPOSE OF REVIEW

To provide a comprehensive review of complementary and alternative medicine (CAM) treatments for children and adolescents with attention deficit hyperactivity disorder (ADHD).

RECENT FINDINGS

Many parents of children with ADHD are reluctant to pursue medication options and unable to access behavioral counseling. CAM therapies are often appealing to families and studies show that a large percentage of children with ADHD are treated with one or more CAM therapy. Most research studies evaluating CAM therapies are methodologically flawed, and often times there are inconsistencies across either study design or results. Although the American Academy of Pediatrics does not recommend any CAM therapies for ADHD, essential fatty acid supplementation is likely well tolerated and modestly effective.

SUMMARY

Most complementary and alternative treatments do not have adequate research to recommend their use in children with ADHD. Physicians should be aware of the many CAM treatment options and the research surrounding them in order to provide their patients with the most current and accurate information available.

Dietary and nutritional treatments for attention-deficit/hyperactivity disorder: current research support and recommendations for practitioners

Evidence for dietary/nutritional treatments of attention-deficit/hyperactivity disorder (ADHD) varies widely, from double-blind, placebo-controlled trials to anecdotal. In guiding patients, clinicians can apply the SECS versus RUDE rule: treatments that are Safe, Easy, Cheap, and Sensible (SECS) require less evidence than those that are Risky, Unrealistic, Difficult, or Expensive (RUDE). Two nutritional treatments appear worth general consideration: Recommended Daily Allowance/Reference Daily Intake multivitamin/mineral supplements as a pediatric health intervention not specific to ADHD and essential fatty acids, especially a mix of eicosapentaenoic acid, docosahexaenoic acid, and γ-linolenic acid as an ADHD-specific intervention. Controlled studies support the elimination of artificial food dyes to reduce ADHD symptoms, but this treatment may be more applicable to the general pediatric population than to children with diagnosed ADHD. Mineral supplementation is indicated for those with documented deficiencies but is not supported for others with ADHD. Carnitine may have a role for inattention, but the evidence is limited. Dimethylaminoethanol probably has a small effect. Herbs, although "natural," are actually crude drugs, which along with homeopathic treatments have little evidence of efficacy. Consequences of delayed proven treatments need consideration in the risk-benefit assessment of dietary/nutritional treatments.

Magnesium sulfate and sodium valproate block methylphenidate-induced hyperlocomotion, an animal model of mania

Magnesium sulfate (MgSO4) is used to treat and prevent eclamptic seizures, and several anticonvulsant drugs (e.g., sodium valproate) are clinically effective antimanic drugs. Psychostimulant-induced hyperlocomotion has been proposed as an animal model for the study of antimanic drugs. The present study evaluated the effects of MgSO4 and sodium valproate (as a positive control) on hyperlocomotion induced by methylphenidate in mice. Acute MgSO4 (300-400 mg/kg), but not sodium valproate (100-300 mg/kg), prevented the increase in locomotor activity induced by methylphenidate (5.0 mg/kg). In contrast, repeated treatment (14 days) with valproate (300 mg/kg), but not MgSO4 (400 mg/kg), blocked methylphenidate-induced hyperlocomotion. Thus, acute MgSO4 exerted antimanic-like effects in this animal model.

The mineral depletion of foods available to us as a nation (1940-2002)--a review of the 6th Edition of McCance and Widdowson

Over the past 60 years there have been fundamental changes in the quality and quantity of food available to us as a nation. The character, growing method, preparation, source and ultimate presentation of basic staples have changed significantly to the extent that trace elements and micronutrient contents have been severely depleted. This trend, established in a review of the 5th Edition of McCance & Widdowson's The Composition of Foods, is still apparent in this review of the 6th edition of the same work. Concurrently there has been a precipitous change towards convenience and pre-prepared foods containing saturated fats, highly processed meats and refined carbohydrates, often devoid of vital micronutrients yet packed with a cocktail of chemical additives including colourings, flavourings and preservatives. It is proposed that these changes are significant contributors to rising levels of diet-induced ill health. Ongoing research clearly demonstrates a significant relationship between deficiencies in micronutrients and physical and mental ill health.

Alternative treatments for adults with attention-deficit hyperactivity disorder (ADHD)

A previous review of alternative treatments (Tx) of ADHD--those other than psychoactive medication and behavioral/psychosocial Tx--was supplemented with an additional literature search focused on adults with ADHD. Twenty-four alternative Tx were identified, ranging in scientific documentation from discrediting controlled studies through mere hypotheses to positive controlled double-blind clinical trials. Many of them are applicable only to a specific subgroup. Although oligoantigenic (few-foods) diets have convincing double-blind evidence of efficacy for a properly selected subgroup of children, they do not appear promising for adults. Enzyme-potentiated desensitization, relaxation/EMG biofeedback, and deleading also have controlled evidence of efficacy. Iron supplementation, magnesium supplementation, Chinese herbals, EEG biofeedback, massage, meditation, mirror feedback, channel-specific perceptual training, and vestibular stimulation all have promising prospective pilot data, many of these tests reasonably controlled. Single-vitamin megadosage has some intriguing pilot trial data. Zinc supplementation is hypothetically supported by systematic case-control data, but no systematic clinical trial. Laser acupuncture has promising unpublished pilot data and may be more applicable to adults than children. Essential fatty acid supplementation has promising systematic case-control data, but clinical trials are equivocal. RDA vitamin supplementation, non-Chinese herbals, homeopathic remedies, and antifungal therapy have no systematic data in ADHD. Megadose multivitamin combinations are probably ineffective for most patients and are possibly dangerous. Simple sugar restriction seems ineffective. Amino acid supplementation is mildly effective in the short term, but not beyond 2-3 months. Thyroid treatment is effective in the presence of documented thyroid abnormality. Some alternative Tx of ADHD are effective or probably effective, but mainly for certain patients. In some cases, they are the Tx of choice, and initial evaluation should consider the relevant etiologies. A few have failed to prove effective in controlled trials. Most need research to determine whether they are effective and/or to define the applicable subgroup. Some of them, although not safer than standard Tx, may be preferable for an etiologic subgroup.

Effect of chronic administration of magnesium sulfate on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity in mice

This investigation was aimed to study the effect of magnesium on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in mice. Four groups of mice were given magnesium sulfate (MgSO4.7H2O) in drinking water at four different concentrations of 0.0 g/l (control), 2.5 g/l (low), 5.0 g/l (medium) and 10.0 g/l (high) respectively for a period of 16 weeks; these animals also received MPTP (30 mg/kg, intraperitoneally daily) during the last five days of Mg treatment. Other four groups of mice were given similar dose regimen of MgSO4 but received injections of saline instead of MPTP. Seventy-two hr after the last dose of MPTP, neurobehavioural studies including locomotor activity, pole climbing test and heart nociception test were performed and striata were collected for the analysis of dopamine. The results of this study show that treatment of mice with MgSO4 or MPTP individually has no effect on their behaviour. Concomitant administration of low dose of MgSO4 (2.5 g/l) along with MPTP produced increase in motor activity and latency to heat stimuli; whereas medium and high doses of MgSO4 in combination with MPTP produced opposite (as compared to low dose) effects resulting in a decrease in motor activity and latency to heat stimuli and increase in pole climbing time. However, MgSO4 dose-dependently exacerbated MPTP-induced depletion of striatal dopamine. The mortality was drastically increased (30-55%) in the animals receiving combined treatments of MPTP and MgSO4 as compared to the mice treated with MPTP alone (12%). This study clearly points towards the ability of MgSO4 to modify MPTP-induced neurotoxicity.

Acute and multiple injection effects of magnesium on responding maintained by cocaine, extinction from cocaine, glucose + saccharin, and food

In a variety of behavioral experiments, magnesium has effects that are similar to cocaine and other psychomotor stimulants. Of particular relevance to the present experiments is the recent finding that magnesium maintains responding in cocaine-trained rats. It would be expected, therefore, that injections of magnesium would alter the rate of responding maintained by self-administered cocaine in rats. Five experiments examined the specificity and selectivity of this interaction. Acute and multiple injections of MgCl2 (15-250 mg/kg) produced dose-dependent reductions in responding maintained by cocaine (0.1-2 mg/kg/infusion). Testing for acute injection effects occurred following injections, while testing for multiple injection effects occurred prior to daily injections. Doses of 30 and 125 mg/kg MgCl2 reduced responding maintained by doses of cocaine that were below the training dose of 0.75 mg/kg/infusion. MgCl2 in a dose of 250 mg/kg markedly suppressed responding maintained by each dose of cocaine. A magnesium-deficient diet produced a dose-dependent increase in responding maintained by 0.1 mg/kg/infusion cocaine. In order to determine the specificity and selectively of these effects, acute and multiple injections of MgCl2 were examined on glucose + saccharin- and food-maintained responding. The acute effects of MgCl2 injections were specific because food-maintained responding was not affected, except by the highest dose of 250 mg/kg. This demonstrates that lever pressing was not nonspecifically reduced by 30 and 125 mg/kg MgCl2 during cocaine availability. However, the effects on cocaine-maintained responding were not selective for cocaine because glucose + saccharin-maintained responding and responding during extinction from cocaine were affected by MgCl2 in a manner similar to cocaine-maintained responding.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnesium-maintained self-administration responding in cocaine-trained rats

Magnesium chloride (MgCl2) produces behavioral effects similar to those of psychomotor stimulants in a variety of behavioral situations. Because MgCl2 appears to have stimulant properties, the ability of MgCl2 to maintain responding in a rat self-administration paradigm was examined in seven experiments under different access and schedule conditions in cocaine-trained rats. These varied from the availability of MgCl2 for a single day's test session subsequent to 1 h availability of cocaine, to the availability of MgCl2 for 10 or 20 days after cocaine availability was totally discontinued. Fixed ratio 1, fixed ratio 5, and progressive ratio 1, 2 and 3 schedules of drug delivery were used. The results demonstrate that MgCl2 may substitute for self-administered cocaine because it maintained responding; it did so dose dependently to maintain a constant level of MgCl2 intake; and it did so over a 10-day period of time both with and without access to cocaine on test days. Responding maintained by MgCl2 when cocaine was no longer available was similar under fixed ratio 1 and 5 schedule conditions. The progressive ratio breakpoints for MgCl2 were significantly higher than those for saline, but significantly lower than those for cocaine. These data indicate that MgCl2 has some reinforcing efficacy in cocaine-trained rats, particularly under fixed ratio 1 and 5 schedules, but has a low abuse potential compared to cocaine.

Magnesium-induced conditioned place preference in mice

A conditioned place preference procedure was used in mice to test the hypothesis that magnesium possesses reinforcing properties. Mice were conditioned to the nonpreferred end of a three-compartment straight shuttle box with MgCl2 injections alternating with saline injections on the preferred end. Dose of MgCl2 was varied (0, 15, 30, 125 mg/kg) as well as number of conditioning trials (8 or 16). On the day after the first postconditioning test, animals were given acute injections of 5 mg/kg cocaine, or other test drug, to determine if the conditioned effect on behavior would be potentiated, maintained or blocked by these test drugs. Results demonstrated that 15 mg/kg MgCl2 induced the greatest amount of conditioning and that increasing the number of MgCl2/place pairings did not enhance the amount of conditioning, but rather, it decreased it. Amphetamine potentiated MgCl2-induced place preference; cocaine and pentobarbital maintained it; and haloperidol blocked it. These data indicate that MgCl2 has some primary reinforcing properties in mice and that MgCl2 shares stimulus properties with other stimulants and reinforcing substances.

Postconditioning effects of magnesium on cocaine conditioned place preference in mice

Magnesium chloride (MgCl2) has recently been shown to have stimulant-like properties. Because stimulants are known to induce conditioned place preference (CPP), the CPP procedure was used to test the hypothesis that cocaine and MgCl2 share similar stimulus properties. This would be shown if cocaine-induced CPP could be enhanced in a postconditioning preference test by MgCl2 and other stimulants. Mice were conditioned with 5.0 mg/kg cocaine to the nonpreferred end of a three-compartment straight shuttle box. All groups showed significant shifts in preference from the preconditioning test to the postconditioning test. There were no changes in place preference over test days in mice that were injected only with saline and therefore not conditioned. When animals were given acute injections of either saline, 5.0 mg/kg cocaine, 1.0 mg/kg amphetamine, 30 mg/kg MgCl2, 10 mg/kg pentobarbital, or 0.25 mg/kg haloperidol following conditioning with cocaine, amphetamine and MgCl2 elevated the conditioned cocaine effect, and pentobarbital and haloperidol decreased the conditioned cocaine effect compared to saline. In addition, there was a dose-dependent influence of MgCl2, with 30 mg/kg producing the maximum effect on the conditioned cocaine effect.

Enhancement of apomorphine and l-amphetamine-induced behaviors by magnesium

The behavioral effects of magnesium suggest that this divalent cation has psychomotor stimulant-like properties. Because deficiencies of this cation lead to reductions in drug-induced behaviors dependent on the levels of norepinephrine and dopamine, and numerous in vitro studies have demonstrated a relationship between magnesium and catecholamine activity, the present experiments investigate whether administration of magnesium will lead to increases in stereotyped and locomotor behaviors induced by apomorphine and l-amphetamine. Such changes would suggest that magnesium is increasing the activity of catecholamines in vivo. The results demonstrate that magnesium dose dependently increases the potency of these drugs by producing greater behavioral effects at certain drug doses, by producing shifts to the left in dose-response functions, and by producing decreases in the ED50 as dose of magnesium increases.

Failure of magnesium to maintain self-administration in cocaine-naive rats

Previous research has shown that magnesium interacts with cocaine in such a way that it potentiates its action in a variety of behavioral situations. More recently, it has been demonstrated that magnesium will dose dependently substitute for cocaine self-administration and reduce the intake of cocaine. It is of considerable interest to determine if magnesium would be self-administered in cocaine-naive animals. The results of two experiments demonstrate that magnesium is not self-administered by cocaine-naive rats since although responding for magnesium chloride is above hypertonic saline control levels on day 1 of access, this responding is not maintained on subsequent days, does not occur in a regularly spaced pattern over time, and is not inversely related to dose. Taken together these data indicate that magnesium is a substitute for cocaine that has low abuse potential.

Magnesium alters the potency of cocaine and haloperidol on mouse aggression

Magnesium has been shown to have certain behavioral effects similar to the stimulants cocaine and amphetamine, particularly on mouse resident-intruder aggression. Consequently, it was hypothesized that magnesium should interact with the indirect agonist cocaine and the antagonist haloperidol to alter their potency in the mouse resident-intruder model. Acute and chronic drug effects were compared. Results demonstrate an enhancement of cocaine potency by 30 and 125 mg/kg MgCl2 and a lowering of cocaine potency by a 15% required-Mg2+ deficient diet as measured by shifts in the dose response to acutely administered cocaine. Following chronic 0.5 mg/kg cocaine for 15 days, a dose of 125 mg/kg acutely administered MgCl2 prevented the disruptive effects of chronic cocaine on mouse aggression. Acutely administered haloperidol was influenced by Mg2+ treatments in a manner opposite from the effects on cocaine, while the chronic effects of haloperidol were affected in the same manner by Mg2+ treatments as those shown for chronic cocaine. Several mechanisms are suggested to explain these interactions.