Persistent GABAA/C responses to gabazine, taurine and beta-alanine in rat hypoglossal motoneurons

Cognitive and negative symptoms in schizophrenia with L-Carnosine adjuvant therapy - A randomized double-blind placebo-controlled study

The antioxidant L-Carnosine is reported to improve negative and cognitive symptoms in Schizophrenia. A randomized double-blind placebo-controlled study was planned to study the effectiveness of adjuvant L-Carnosine therapy in patients with Schizophrenia. 100 eligible patients with predominant negative symptoms as measured by scale for assessment of negative symptoms (SANS total score ≥ 60) and Schizophrenia diagnosis (International Classification of Disorder-Tenth Edition, ICD-10) were recruited. They were randomly allocated to receive a fixed dose of either 400 mg L-Carnosine or identical placebo for 3 months and increased to 800 mg from 13th week till completion of study. Primary outcome measures assessed changes in SANS scores with L-Carnosine at 24 weeks compared to baseline, 4 and 12 weeks. Secondary outcome measures were done to assess the improvement in cognitive symptoms (executive function, attention, and memory) at 24 weeks using subtests of NIMHANS (National Institute for Mental Health and Neurosciences) cognitive battery. Side effects were assessed using adverse events reporting form. The attention scores (p = .023) showed significant differences in patients receiving 800 mg of L-Carnosine at the end of the study. There were no significant differences in negative symptoms in the two arms at study completion. L-Carnosine dosing of 800 mg may be a promising agent to enhance executive functions in Schizophrenia.

Oral Supplementation with L-Carnosine Attenuates Social Recognition Deficits in CD157KO Mice via Oxytocin Release

The outcomes of supplementation with L-carnosine have been investigated in clinical trials in children with autism spectrum disorder (ASD). However, reports on the effects of L-carnosine in humans have been inconsistent, and the efficacy of L-carnosine supplementation for improving ASD symptoms has yet to be investigated in animal studies. Here, we examined the effects of oral supplementation with L-carnosine on social deficits in CD157KO mice, a murine model of ASD. Social deficits in CD157KO mice were assessed using a three-chamber social approach test. Oral supplementation with L-carnosine attenuated social behavioral deficits. The number of c-Fos-positive oxytocin neurons in the supraoptic nucleus and paraventricular nucleus was increased with L-carnosine supplementation in CD157KO mice after the three-chamber social approach test. We observed an increase in the number of c-Fos-positive neurons in the basolateral amygdala, a brain region involved in social behavior. Although the expression of oxytocin and oxytocin receptors in the hypothalamus was not altered by L-carnosine supplementation, the concentration of oxytocin in cerebrospinal fluid was increased in CD157KO mice by L-carnosine supplementation. These results suggest that L-carnosine supplementation restores social recognition impairments by augmenting the level of released oxytocin. Thus, we could imply the possibility of a safe nutritional intervention for at least some types of ASD in the human population.

The Potential of Carnosine in Brain-Related Disorders: A Comprehensive Review of Current Evidence

Neurological, neurodegenerative, and psychiatric disorders represent a serious burden because of their increasing prevalence, risk of disability, and the lack of effective causal/disease-modifying treatments. There is a growing body of evidence indicating potentially favourable effects of carnosine, which is an over-the-counter food supplement, in peripheral tissues. Although most studies to date have focused on the role of carnosine in metabolic and cardiovascular disorders, the physiological presence of this di-peptide and its analogues in the brain together with their ability to cross the blood-brain barrier as well as evidence from in vitro, animal, and human studies suggest carnosine as a promising therapeutic target in brain disorders. In this review, we aim to provide a comprehensive overview of the role of carnosine in neurological, neurodevelopmental, neurodegenerative, and psychiatric disorders, summarizing current evidence from cell, animal, and human cross-sectional, longitudinal studies, and randomized controlled trials.

Metabolomic analysis of mouse prefrontal cortex reveals upregulated analytes during wakefulness compared to sleep

By identifying endogenous molecules in brain extracellular fluid metabolomics can provide insight into the regulatory mechanisms and functions of sleep. Here we studied how the cortical metabolome changes during sleep, sleep deprivation and spontaneous wakefulness. Mice were implanted with electrodes for chronic sleep/wake recording and with microdialysis probes targeting prefrontal and primary motor cortex. Metabolites were measured using ultra performance liquid chromatography-high resolution mass spectrometry. Sleep/wake changes in metabolites were evaluated using partial least squares discriminant analysis, linear mixed effects model analysis of variance, and machine-learning algorithms. More than 30 known metabolites were reliably detected in most samples. When used by a logistic regression classifier, the profile of these metabolites across sleep, spontaneous wake, and enforced wake was sufficient to assign mice to their correct experimental group (pair-wise) in 80-100% of cases. Eleven of these metabolites showed significantly higher levels in awake than in sleeping mice. Some changes extend previous findings (glutamate, homovanillic acid, lactate, pyruvate, tryptophan, uridine), while others are novel (D-gluconate, N-acetyl-beta-alanine, N-acetylglutamine, orotate, succinate/methylmalonate). The upregulation of the de novo pyrimidine pathway, gluconate shunt and aerobic glycolysis may reflect a wake-dependent need to promote the synthesis of many essential components, from nucleic acids to synaptic membranes.

Taurine Administration Recovers Motor and Learning Deficits in an Angelman Syndrome Mouse Model

Angelman syndrome (AS, MIM 105830) is a rare neurodevelopmental disorder affecting 1:10–20,000 children. Patients show moderate to severe intellectual disability, ataxia and absence of speech. Studies on both post-mortem AS human brains and mouse models revealed dysfunctions in the extra synaptic gamma-aminobutyric acid (GABA) receptors implicated in the pathogenesis. Taurine is a free intracellular sulfur-containing amino acid, abundant in brain, considered an inhibiting neurotransmitter with neuroprotective properties. As taurine acts as an agonist of GABA-A receptors, we aimed at investigating whether it might ameliorate AS symptoms. Since mice weaning, we orally administered 1 g/kg/day taurine in water to Ube3a-deficient mice. To test the improvement of motor and cognitive skills, Rotarod, Novel Object Recognition and Open Field tests were assayed at 7, 14, 21 and 30 weeks, while biochemical tests and amino acid dosages were carried out, respectively, by Western-blot and high-performance liquid chromatography (HPLC) on frozen whole brains. Treatment of Ube3a^m−/p+ mice with taurine significantly improved motor and learning skills and restored the levels of the post-synaptic PSD-95 and pERK1/2-ERK1/2 ratio to wild type values. No side effects of taurine were observed. Our study indicates taurine administration as a potential therapy to ameliorate motor deficits and learning difficulties in AS.

Taurine as an Essential Neuromodulator during Perinatal Cortical Development

A variety of experimental studies demonstrated that neurotransmitters are an important factor for the development of the central nervous system, affecting neurodevelopmental events like neurogenesis, neuronal migration, programmed cell death, and differentiation. While the role of the classical neurotransmitters glutamate and gamma-aminobutyric acid (GABA) on neuronal development is well established, the aminosulfonic acid taurine has also been considered as possible neuromodulator during early neuronal development. The purpose of the present review article is to summarize the properties of taurine as neuromodulator in detail, focusing on the direct involvement of taurine on various neurodevelopmental events and the regulation of neuronal activity during early developmental epochs. The current knowledge is that taurine lacks a synaptic release mechanism but is released by volume-sensitive organic anion channels and/or a reversal of the taurine transporter. Extracellular taurine affects neurons and neuronal progenitor cells mainly via glycine, GABA(A), and GABA(B) receptors with considerable receptor and subtype-specific affinities. Taurine has been shown to directly influence neurogenesis in vitro as well as neuronal migration in vitro and in vivo. It provides a depolarizing signal for a variety of neuronal population in the immature central nervous system, thereby directly influencing neuronal activity. While in the neocortex, taurine probably enhance neuronal activity, in the immature hippocampus, a tonic taurinergic tone might be necessary to attenuate activity. In summary, taurine must be considered as an essential modulator of neurodevelopmental events, and possible adverse consequences on fetal and/or early postnatal development should be evaluated for pharmacological therapies affecting taurinergic functions.

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

This study investigated the benefit of β-alanine (BA) supplementation on behavioral and cognitive responses relating to mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) in rats exposed to a low-pressure blast wave. Animals were fed a normal diet with or without (PL) BA supplementation (100 mg kg⁻¹) for 30-day, prior to being exposed to a low-pressure blast wave. A third group of animals served as a control (CTL). These animals were fed a normal diet, but were not exposed to the blast. Validated cognitive-behavioral paradigms were used to assess both mTBI and PTSD-like behavior on days 7–14 following the blast. Brain-derived neurotrophic factor (BDNF), neuropeptide Y, glial fibrillary acidic protein (GFAP) and tau protein expressions were analyzed a day later. In addition, brain carnosine and histidine content was assessed as well. The prevalence of animals exhibiting mTBI-like behavior was significantly lower (p = 0.044) in BA than PL (26.5 and 46%, respectively), but no difference (p = 0.930) was noted in PTSD-like behavior between the groups (10.2 and 12.0%, respectively). Carnosine content in the cerebral cortex was higher (p = 0.048) for BA compared to PL, while a trend towards a difference was seen in the hippocampus (p = 0.058) and amygdala (p = 0.061). BDNF expression in the CA1 subregion of PL was lower than BA (p = 0.009) and CTL (p < 0.001), while GFAP expression in CA1 (p = 0.003) and CA3 (p = 0.040) subregions were higher in PL than other groups. Results indicated that BA supplementation for 30-day increased resiliency to mTBI in animals exposed to a low-pressure blast wave.