Low-dose L-methionine-associated Changes in Behavioural Indices in Young Rats

Abstract

Objective: The study objectives were to investigate the effects of L-methionine (at low doses) on open-field novelty-induced behaviours, anxiety-related behaviours, working-memory and brain S-adenosyl-methionine (SAMe) levels in young rats. This was with a view to determine whether administration of low doses of L-methionine can significantly alter behavioural parameters, working-memory and brain SAMe levels, or not. Methodology: Wistar rats (40-45 g each) were given distilled water or L-methionine (5 and 10 mg/kg body weight) orally for 21 days. Behaviours were assessed after the first and last dose of L-methionine. Results: In the open field, significant increases in horizontal locomotion and rearing were seen after the first dose, while repeated administration led to their suppression. Suppression of grooming behaviour was observed at both times of assessment. Working-memory in the radial-arm maze was significantly reduced following repeated administration; while the elevated plus-maze test revealed anxiolytic responses following both acute and repeated administration. Patterns of changes in horizontal locomotion in the y-maze and radial-arm maze were similar to that of the open-field. There was no significant difference in brain levels of SAMe at end of study. Conclusion: The study demonstrated an association between low dose L-methionine administration and behavioural changes in young rats. It therefore brings to light, the behavioural changes that may occur due to addition of low doses of L-methionine to the diet.

Antidepressant and Anxiolytic Effects of L-Methionine in the WAG/Rij Rat Model of Depression Comorbid with Absence Epilepsy

“…The fact that L-MET at the dose of 50 mg/kg was the most effective in suppressing SWDs in WAG/Rij rats and that this effect appeared by the 4th hour after administration confirms previously published data [36]. Our findings concerning the anxiolytic-like effect of L-MET in WAG/Rij rats are consistent with the data of others who have shown an anxiolytic-like effect of low doses (5 and 10 mg/kg) of L-MET treatment comparable to that of diazepam in the elevated plus-maze test in Wistar rats [39]. It should be noted that the anxiolytic and antidepressant-like effects of SAMe have been well-documented previously [39,64,66,69].…”

“…Moreover, it is not clear whether L-MET can have antiepileptic activity. Several studies focus on the effect of L-MET on locomotor and exploratory activity, anxiety level, memory, and convulsive seizures (kainate model of temporal lobe epilepsy) [39,40]. However, there are no studies of the effects of L-MET on depression associated with absence epilepsy in experimental models of this pathology.…”

Cucumeropsis mannii reverses high-fat diet induced metabolic derangement and oxidative stress

“…The stimulation of the inhibitory neurotransmitter gamma amino-butyric acid (GABA) receptors has also been associated with locomotor retardation or a central depressant response. Studies have also shown that the activation of A and B subtypes of the GABA receptors reduces grooming frequency (66,69). The result of brain GABA levels in this study also supports the inhibitory response observed, although the rich essential amino acid content of C. mannii (4, 26) could also alter neurotransmitter balance in favour of a central inhibitory response.…”

“…While there is a dearth of scientific studies examining the central nervous system effects of C. mannii, central depressant effects of a given compound or drug have been attributed to their ability to downregulate or upregulate excitatory or inhibitory neurotransmitters respectively. Alterations in horizontal locomotion or grooming in the open field has been associated with changes in the activity of dopamine (DA) in a number of studies (65,66). Methylation at the DA receptors, synaptic cleft or receptor-bound DA (67,68), and inhibition of ligand gating to dopamine also results in a downregulation of DA receptors, resulting in locomotor retardation or a reduction of self-grooming.…”

A Photoelectrochemical Sensor Based on DNA Bio-Dots-Induced Aggregation of AuNPs for Methionine Detection

“…Methionine (Met) is an essential amino acid that plays a vital role in cell metabolism, immune cell production, normal nerve function, growth and development, and many other tissue functions [1][2][3]. At the same time, Met plays an important role in human physiological and pathological processes.…”