Aleksandra Szopa

Magnesium in depression

Magnesium is one of the most essential mineral in the human body, connected with brain biochemistry and the fluidity of neuronal membrane. A variety of neuromuscular and psychiatric symptoms, including different types of depression, was observed in magnesium deficiency. Plasma/serum magnesium levels do not seem to be the appropriate indicators of depressive disorders, since ambiguous outcomes, depending on the study, were obtained. The emergence of a new approach to magnesium compounds in medical practice has been seen. Apart from being administered as components of dietary supplements, they are also perceived as the effective agents in treatment of migraine, alcoholism, asthma, heart diseases, arrhythmias, renal calcium stones, premenstrual tension syndrome etc. Magnesium preparations have an essential place in homeopathy as a remedy for a range of mental health problems. Mechanisms of antidepressant action of magnesium are not fully understood yet. Most probably, magnesium influences several systems associated with development of depression. The first information on the beneficial effect of magnesium sulfate given hypodermically to patients with agitated depression was published almost 100 years ago. Numerous pre-clinical and clinical studies confirmed the initial observations as well as demonstrated the beneficial safety profile of magnesium supplementation. Thus, magnesium preparations seem to be a valuable addition to the pharmacological armamentarium for management of depression.

Effects of ifenprodil on the antidepressant-like activity of NMDA ligands in the forced swim test in mice

Multiple pre-clinical and clinical studies clearly displayed implication of the NMDA receptors in development of depressive disorders since a variety of NMDA receptor antagonists exhibit an antidepressant-like effect. The main aim of our study was to assess the influence of ifenprodil - an allosteric modulator selectively binding at the NR2B subunit on the performance in the forced swim test in mice of various NMDA receptor ligands interacting with distinct components of the NMDA receptor complex. Ifenprodil at a dose of 10mg/kg enhanced the antidepressant-like effect of CGP 37849 (a competitive NMDA receptor antagonist, 0.312mg/kg), L-701,324 (an antagonist at glycine site, 1mg/kg), MK-801 (a non-competitive antagonist, 0.05mg/kg) and d-cycloserine (a partial agonist of a glycine site, 2.5mg/kg) but it did not shorten the immobility time of animals which concurrently received an inorganic modulator of the NMDA receptor complex, such as Zn(2+) (2.5mg/kg) or Mg(2+) (10mg/kg). On the other hand, the antidepressant-like effect of ifenprodil (20mg/kg) was reversed by N-methyl-d-aspartic acid (an agonist at the glutamate site, 75mg/kg) or d-serine (an agonist at the glycine site, 100nmol/mouse). In conclusion, the antidepressant-like potential of ifenprodil given concomitantly with NMDA ligands was either reinforced (in the case of both partial agonist and antagonists, except for magnesium and zinc) or diminished (in the case of conventional full agonists).

The influence of caffeine on the activity of moclobemide, venlafaxine, bupropion and milnacipran in the forced swim test in mice.

AIMS Worrying data indicate that excessive caffeine intake applies to patients suffering from mental disorders, including depression. It is thus possible to demonstrate the usefulness of caffeine and its derivatives in the treatment of depression. The main goal of the present studywas to evaluate the influence of caffeine (5mg/kg) on the activity of moclobemide (1.5 mg/kg), venlafaxine (1 mg/kg), bupropion (10 mg/kg), and milnacipran (1.25 mg/kg). Moreover, we assessed the influence of caffeine on their serum and brain levels using highperformance liquid chromatography. MAIN METHODS The experiment was carried out on naïve adult male Albino Swiss mice. Caffeine and tested drugs were administered intraperitoneally. The influence of caffeine on the activity of selected antidepressant drugs was evaluated in forced swim test (FST). Locomotor activity was estimated to verify and exclude false positive/negative results. To assess the influence of caffeine on the levels of studied antidepressant drugs, their concentrations were determined in murine serum and brains using high-performance liquid chromatography. KEY FINDINGS Caffeine potentiated activity of all antidepressants examined in FST and the observed effects were not due to the increase in locomotor activity in the animals. Only in the case of co-administration of caffeine and milnacipran an increased milnacipran concentration in serum was observed without affecting its concentration in the brain. SIGNIFICANCE Caffeine potentiates the activity of antidepressant drugs from different chemical groups. The interactions of caffeine with venlafaxine, bupropion and moclobemide occur in pharmacodynamic phase, whereas the interaction of caffeine–milnacipran occurs, at least partially, in pharmacokinetic phase.

Traxoprodil augments the antidepressant-like activity of agomelatine but not of mianserin or tianeptine in the forced swim test in mice

BACKGROUND The main objective of our study was to evaluate the influence of traxoprodil on the activity of the atypical antidepressant drugs (agomelatine, mianserin, tianeptine). METHODS The forced swim test (FST) in mice was used to determine the antidepressant-like activity of the tested agents. Drugs levels in brain tissue were assessed by a high performance liquid chromatography method. RESULTS Concurrent intraperitoneal administration of per se ineffective doses of traxoprodil (10mg/kg) and agomelatine (20mg/kg) shortened the immobility time of animals in the FST. The observed effect was associated with elevated brain levels of traxoprodil. Similar interaction was not detected for traxoprodil and mianserin (10mg/kg) or tianeptine (15mg/kg). CONCLUSION Traxoprodil-agomelatine interaction is pharmacokinetic in nature. A combination of these agents has a potential to become an interesting strategy in the treatment of depression.

The effect of an acute and 7-day administration of magnesium chloride on magnesium concentration in the serum, erythrocytes, and brain of rats.

BACKGROUND Magnesium (Mg) is one of the most essential cations in human body that is involved in a variety of physiological processes. Despite the variations in the extracellular Mg level, specific transport systems are involved in maintaining the intracellular free Mg at a relatively constant level. We aimed to investigate the changes of Mg level in the brain, erythrocytes, and serum of rats after an acute and subchronic administration of Mg. METHODS Magnesium chloride (MgCl2) solution was administered intraperitoneally (ip) either once at a dose of 50mg/kg or for 7 days at a single daily dose of 50mg/kg. Blood and brains of animals were collected 15, 30, 60, 120, and 240min after the acute or the last injection. Total Mg concentration in blood serum, erythrocytes, and the whole brain was determined spectrophotometrically. RESULTS The highest Mg concentration was detected in the brain tissue, while the most significant changes in Mg level were found in serum. CONCLUSIONS Neither the brain nor the erythrocyte showed a change in the Mg level considerably after an increase in serum Mg level induced by the acute and subchronic administration of MgCl2 solution.

Chronic treatment with caffeine and its withdrawal modify the antidepressant-like activity of selective serotonin reuptake inhibitors in the forced swim and tail suspension tests in mice. Effects on Comt, Slc6a15 and Adora1 gene expression

&NA; Recent preclinical and clinical data suggest that low dose of caffeine enhances the effects of common antidepressants. Here we investigated the effects of chronic administration of caffeine (5 mg/kg, twice daily for 14 days) and its withdrawal on day 15th on the activity of per se ineffective doses of fluoxetine (5 mg/kg) and escitalopram (2 mg/kg) given on day 15th. We found decreased immobility time in the forced swim and tail suspension tests in mice in which caffeine was administered simultaneously with antidepressants on day 15th following a 14‐day caffeine treatment and no alterations in the spontaneous locomotor activity. A decrease in the level of escitalopram and an increase in the level of caffeine in serum were observed after concomitant administration of these compounds, while the joint administration of caffeine and fluoxetine was not associated with changes in their levels in serum or brain. Caffeine withdrawal caused a decrease in Adora1 mRNA level in the cerebral cortex (Cx). Administration of escitalopram or fluoxetine followed by caffeine withdrawal caused an increase in this gene expression, whereas administration of escitalopram, but not fluoxetine, on day 15th together with caffeine caused a decrease in Adora1 mRNA level in the Cx. Furthermore, antidepressant‐like activity observed after joint administration of the tested drugs with caffeine was associated with decreased Slc6a15 mRNA level in the Cx. The results show that withdrawal of caffeine after its chronic intake may change activity of antidepressants with concomitant alterations within monoamine, adenosine and glutamate systems. HighlightsCaffeine was administered for 14 days and on day 15th it was withdrawn.Ineffective doses of fluoxetine or escitalopram (FLX/ESC) were administered on day 15th.FLX/ESC given together with caffeine displayed antidepressant‐like activity.Caffeine and FLX/ESC modified Adora1 and Slc6a15 mRNA level in the cerebral cortex.Caffeine withdrawal after its chronic intake may change activity of FLX/ESC.

NMDA receptor activation antagonizes the NMDA antagonist-induced antianxiety effect in the elevated plus-maze test in mice

BACKGROUND The purpose of this study was to determine how the activation of different regulatory domains of the NMDA complex affects the antianxiety effect of antagonists acting at its distinct binding sites. METHODS The anxiolytic-like activity was assessed by the elevated plus-maze test in mice. RESULTS The anxiolytic activity of CGP 37849 (a competitive NMDA receptor antagonist) and L-701,324 (an antagonist at glycine site) was confirmed, but effects of both were significantly reduced by N-methyl-D-aspartic acid (NMDA) or by D-serine agonists at glutamate and glycine site of the NMDA receptor complex, respectively. CONCLUSION The obtained data suggest that stimulation of the glutamate or glycine recognition site of the NMDA receptor complex significantly decreases the antianxiety properties of antagonists of either site.

8-Cyclopentyl-1,3-dimethylxanthine enhances effectiveness of antidepressant in behavioral tests and modulates redox balance in the cerebral cortex of mice

The objective of our study was to investigate whether 8-cyclopentyl-1,3-dimethylxanthine (CPT), associated with the adenosine system, enhances the antidepressant efficacy of antidepressant. All experiments were carried out on Albino Swiss mice. Following drugs: CPT (3 mg/kg) and imipramine (15 mg/kg) were administered intraperitoneally (ip), 60 min before tests. Two behavioral tests on antidepressant capability – a forced swim test (FST) and a tail suspension test (TST) – were performed. To examine whether co-administration of CPT with antidepressants affects the redox balance, the lipid peroxidation products (LPO), glutathione (GSH), glutathione disulfide (GSSG), nicotinamide adenine dinucleotide phosphate (NADP+), and reduced nicotinamide adenine dinucleotide phosphate (NADPH) were determined in the cerebral cortex. The results have demonstrated a CPT-induced enhancement of the antidepressant-like effect of imipramine both in the FST and TST, which may indicate that the adenosine system may be involved in the increasing the effect of antidepressant. Co-administration of CPT with imipramine, such as imipramine alone, decreased the NADP+ and LPO concentrations and increased the GSH/GSSG ratio in comparison to the control, which may confirm beneficial – but comparable to imipramine – effect on redox balance under environmental stress conditions. An increase in the concentration of GSSG in the cortex of animals treated with imipramine in ineffective dose compared to control and no such changes after combined administration of both drugs may suggest a favorable oxidation-reduction potential resulting from their synergistic antidepressant effect.

The positive synergism of CPT and MK-801 in behavioral tests and in reduction of environmental stress and redox signaling changes in mice cerebral cortex.

BACKGROUND Depressive disorders are associated with oxidative stress. Therefore, it is interesting if antidepressants can affect redox equilibrium and signaling. The first step of our study was to determine the influence of the adenosine system on the antidepressant-like activity of noncompetitive antagonist of the NMDA (N-methyl-d-aspartate) receptor complex - dizocilpine (MK- 801). To this aim, two behavioral tests commonly used to assess the antidepressant capability of drugs - the forced swim test (FST) and tail suspension test (TST), were performed. Locomotor activity was estimated to verify and exclude false positive/negative results in the FST and TST. To examine whether antidepressants affect redox equilibrium, we have investigated lipid peroxidation products (LPO), GSH (glutathione), GSSG (glutathione disulfide), NADP+ (nicotinamide adenine dinucleotide phosphate) and NADPH (reduced nicotinamide adenine dinucleotide phosphate) in the cerebral cortex of mice following administration of CPT (8-cyclopentyl-1,3-dimethylxanthine) and MK-801 (dizocilpine) under environmental stress conditions. METHOD The experiments were carried out using male Albino Swiss mice (25-30 g). The drugs were administered ip., alone and simultaneously, 60 min before tests. RESULTS The behavioural tests results showed that CPT (3 mg/kg) potentiated the antidepressant-like activity of MK-801 (0.05 mg/kg) and the observed effects were not due to the increase in mice locomotor activity. Positive synergism of CPT and MK-801 in reduction of environmental stress conditions was revealed. In this group an increase in GSH and GSSG without changes in GSH/GSSG ratio and reduction of LPO was found. The level of lipid peroxidation products was also decreased in group receiving CPT and MK-801 separately. CONCLUSION Examined antidepressant agents may increase antioxidant defences however further studies are needed with different range of time.

Cannabinoids in depressive disorders

&NA; Cannabis sativa is one of the most popular recreational and medicinal plants. Benefits from use of cannabinoid agents in epilepsy, multiple sclerosis, Parkinsons disease, Alzheimers disease, and others have been suggested. It seems that the endocannabinoid system is also involved in the pathogenesis and treatment of depression, though its role in this mental disease has not been fully understood yet. Both the pro‐ and antidepressant activity have been reported after cannabis consumption and a number of pre‐clinical studies have demonstrated that both agonist and antagonist of the endocannabinoid receptors act similarly to antidepressants. Responses to the cannabinoid agents are relatively fast, and most probably, the noradrenergic, serotoninergic, glutamatergic neurotransmission, neuroprotective activity, as well as modulation of the hypothalamic‐pituitary‐adrenal axis are implicated in the observed effects. Based on the published data, the endocannabinoid system evidently gives novel ideas and options in the field of antidepressant treatment, however further studies are needed to determine which group of patients could benefit from this type of therapy.