[The characterization of central neuromediation in rats fed with magnesium-deprived diet before and after magnesium replenishment].

Abstract

Magnesium (Mg) has been proposed to take part in biochemical dysregulation contributing to psychiatric disorders. The aims of this study was to estimate acute behavioural responses to clonidine (0.1 mg/kg i.p.), d-amphetamine (5 mg/kg, i.p), arecoline (15 mg/kg i.p), nicotine (6 mg/kg i.p.), apomorphine (1.5 mg/kg i.p.) and L-5-hydroxytryptophan (300 mg/kg i.p.) in rats fed with Mg-deprivated diet for 49 days and then treated with organic and inorganic Mg salts (50 mg Mg per kg) ether alone or in combination with pyridoxine (5 mg vitamin B6 per kg). In our study Mg-deficient rats were more sensitive to d-amphetamine-induced motor stereotypes compared with control rats; time of onset of the stereotypies insignificantly decreased by 14.89% and duration of the stereotypies significantly increased by 19.44% (320.36 +/- 19.90 vs. 268.23 +/- 8.17 minutes; p = 0.043). Mg deficiency did not modulate sensitivity to nicotine-induced seizure. The time between nicotine injection and emergence of clonic seizure (seizure latency) in the controls and Mg-deficient rats were 0.80 +/- 0.26 and 0.96 +/- 0.21 minutes respectively. Duration of the seizures in the controls and Mg-deficient rats were 64.93 +/- 7.20 and 79.32 +/- 8.13 minutes. In our study, Mg deficiency did not affect on clonidine- and apomorphine-induced hypothermia. Clonidine produced similar decreases in rectal temperature in controls and Mg-deficient group. In experiments using apomorphine, values of hypothermia were similar to those observed with clonidine. Mg deficiency antagonized 5-hydroxytryptophan-induced head-twitch response. The number of head twitches produced by 5-hydroxytryptophan was significantly (p = 0.49) decreased: twofold in magnesium-deficient rats (1.23 +/- 0.44 per minute) as compared with controls (2.42 +/- 0.52 per minute). Arecoline-induced tremor was comparably less expressed in Mg-deficient rats than in controls. The time between arecoline injection and time of onset of the tremor in the controls and Mg-deficient rats were 92.75 +/- 19.35 and 245.17 +/- 121.86 seconds respectively (p < or = 0.035). Duration of the tremors in the controls and Mg-deficient rats were 1175.58 +/- 127.87 and 703.83 +/- 89.33 seconds (p = 0.015). Magnesium salts (Mg chloride, Mg L-aspartate alone and in combination with B6) were administered through gastric tube during twenty days up to complete compensation oferythrocyte and plasma Mg levels in all experimental groups. In our study administration of Mg salts resulted in normalization of acute behavioural responses in Mg-deficient rats to d-amphetamine, arecoline, and L-5-hydroxytryptophan. Behavioural responses in rats treated with both Mg chloride and Mg L-aspartate in combinations with B6 were comparable with those observed in MagneB6 treatment.

• Authors: A A Spasov, I N Iezhitsa, M S Kravchenko, M V Kharitonova
• Journal: Rossiiskii fiziologicheskii zhurnal imeni I.M. Sechenova (Ross Fiziol Zh Im I M Sechenova) Vol. 94 Issue 7 Pg. 822-33 (Jul 2008) ISSN: 0869-8139 [Print] Russia (Federation)
• PMID: 18767395 (Publication Type: English Abstract, Journal Article)

Chemical References

• Cations, Divalent
• Neurotransmitter Agents
• Vitamins
• Magnesium Chloride
• Aspartic Acid
• Vitamin B 6
• Magnesium

Topics

• Animals
• Aspartic Acid (pharmacology)
• Cations, Divalent
• Diet
• Magnesium (blood, pharmacology)
• Magnesium Chloride (pharmacology)
• Magnesium Deficiency (physiopathology, psychology)
• Male
• Motor Activity (drug effects)
• Neurotransmitter Agents (physiology)
• Rats
• Reaction Time
• Seizures (physiopathology)
• Stereotyped Behavior (drug effects)
• Vitamin B 6 (pharmacology)
• Vitamins (pharmacology)