The impact of taurine- and beta-alanine-supplemented diets on behavioral and neurochemical parameters in mice: antidepressant versus anxiolytic-like effects

Abstract

Taurine, a substrate of taurine transporter, has functions as a neuromodulator and antioxidant and beta-alanine, a taurine transporter inhibitor, has a role as a neurotransmitter in the brain, and they were expected to be involved in depression-like behavior and antidepressant treatment. These facts aroused our interest in new capabilities of taurine and beta-alanine. Thus, to investigate the effects of chronic ingestion of taurine- (22.5 mmol/kg diet) supplemented diet and beta-alanine- (22.5 mmol/kg diet) supplemented diet under acute stressful conditions, behavioral changes and brain metabolites were compared with mice fed a control diet. In the open field test, no significant difference was observed in locomotor activity among groups. In the elevated plus-maze test, however, significant increases in the percentage of time spent and entries in the open arms were observed in the beta-alanine-supplemented diet fed group compared to both controls and animals fed with taurine-supplemented diet. Moreover, a significant decrease in the duration of immobility was observed in the taurine-supplemented diet group in the forced swimming test compared to both controls and animals fed with beta-alanine-supplemented diet. Taurine-supplemented diet increased taurine and L: -arginine concentrations in the hypothalamus. In contrast, beta-alanine-supplemented diet decreased the concentration of 5-hydroxyindoleacetic acid, a major metabolite of serotonin, in the hypothalamus. Beta-alanine-supplemented diet also increased carnosine (beta-alanyl-L: -histidine) concentration in the cerebral cortex and hypothalamus, and brain-derived neurotrophic factor concentration in the hippocampus. These results suggested that taurine-supplemented diet had an antidepressant-like effect and beta-alanine-supplemented diet had an anxiolytic-like effect.

Behavioral and inflammatory response in animals exposed to a low-pressure blast wave and supplemented with β-alanine

“…This was thought to be related to elevations observed in brain carnosine, and subsequent protection of brain-derived neurotrophic factor (BDNF) expression in the hippocampus. These changes were consistent with others that have demonstrated an association between elevations in brain carnosine content and BDNF expression (Murakami and Furuse 2010). The mechanism of elevated brain carnosine and maintenance of BDNF expression in the hippocampus is not well-understood, but it may be related to carnosine’s role as a neural protectant through its action as an antioxidant (Kohen et al 1988).…”

Strychnine-sensitive glycine receptors on pyramidal neurons in layers II/III of the mouse prefrontal cortex are tonically activated

“…Additionally, glutamatergic synapses (where concentrations of glycine have been estimated to reach 1 mM) may be a second source of glycine due to synaptic spillover (Vandenberg and Aubrey 2001), although it is believed that GlyTs limit glycine spillover 100-to 1,000-fold (Harsing and Matyus 2013). In addition to glycine, the GlyR partial agonists taurine and ␤-alanine are known to be abundant in the brain (Dahchour et al 2000;Murakami and Furuse 2010), and we show here that exogenous taurine can cause an inward current, supporting its role as a GlyR agonist on PFC PNs. In early postnatal cortical PNs, taurine has been shown to mediate tonic nonsynaptic GlyR activation (Flint et al 1998).…”

Regulation of gut luminal serotonin by commensal microbiota in mice

“…Samples for luminal and tissue 5-HT measurement were prepared according to our previously described methods [20, 23, 25]. In brief, the mice were sacrificed by cervical dislocation, and then parts of the ileum, cecum, and distal colon were prepared as samples.…”