Decreased Brain pH Underlies Behavioral and Brain Abnormalities Induced by Chronic Exposure to Glucocorticoids in Mice.

Depressed patients may exhibit glucocorticoid hypersecretion, suggesting that elevated levels of glucocorticoids may play an important role in the pathophysiology of depression. Some postmortem brain studies have shown decreased pH and increased lactate levels in psychiatric patients, implying involvement of these factors in the pathogenesis. To investigate the effects of glucocorticoids on brain pH and lactate levels, and their roles in depressive symptoms, brain pH and lactate were examined in mice treated with corticosterone (CORT), the major bioactive glucocorticoid in rodents.

Chronic Corticosterone Treatment Decreases Extracellular pH and Increases Lactate Release via PDK4 Upregulation in Cultured Astrocytes.

The pathogenesis of stress-related disorders involves aberrant glucocorticoid secretion, and decreased pH and increased lactate in the brain are common phenotypes in several psychiatric disorders. Mice treated with glucocorticoids develop these phenotypes, but it is unclear how glucocorticoids affect brain pH. Therefore, we investigated the effect of corticosterone (CORT), the main glucocorticoid in rodents, on extracellular pH and lactate release in cultured astrocytes, which are the main glial cells that produce lactate in the brain.

Chronic social defeat stress induces anxiety-like behaviors via downregulation of serotonin transporter in the prefrontal serotonergic system in mice.

The serotonergic (5-HTergic) system is closely involved in the pathophysiology of mood and anxiety disorders and the responsibility of this system may differ for each symptom. In this study, we examined the relationship between the dysfunction of the 5-HTergic system and abnormal behaviors in the social defeat stress model, an animal model of mood and anxiety disorders and in mice with knockdown of Slc6a4, the gene encoding SERT. Monoamine content, serotonin (5-HT) release, 5-HT uptake, 5-HT transporter (SERT) protein levels, and behaviors were investigated in mice subjected to chronic social defeat stress and in mice with knockdown of Slc6a4, in 5-HTergic neurons projecting to the prefrontal cortex (PFC).

2'-Fucosyllactose Alleviates Early Weaning-Induced Anxiety-Like Behavior, Amygdala Hyperactivity, and Gut Microbiota Changes.

Early life stress has a significant impact on development of the central nervous system (CNS), with lasting rather than transient consequences; therefore, it is important to alleviate these effects. In recent years, functional communication between the CNS and gut microbiota through the so-called brain-gut-microbiota axis has been examined, and it is likely that prebiotics contribute to development of the CNS through the gut microbiota. In this study, we performed behavioral, neurohistological, and fecal microbiota analyses in early-weaned mice to examine the effects of 2'-fucosyllactose (2'-FL), a human milk oligosaccharide, on anxiety induced by early life stress.

Methyl Donor Supplementation Prevents a Folate Deficiency-induced Depression-like State and Neuronal Immaturity of the Dentate Gyrus in Mice.

We have recently shown that folate deficiency induces depression-like behavior and neuronal immaturity in the dentate gyrus (DG) in mice. We also revealed that folate deficiency inhibits neuronal maturation, hypomethylates the promoter of certain neuronal genes and decreases intracellular levels of S-adenosylmethionine (SAM), a methyl donor, in cultured neural stem and progenitor cells. Based on these findings, we hypothesized that SAM reduction may be involved in a folate deficiency-induced depressive state and neural immaturity.

Kihito prevents corticosterone-induced brain dysfunctions in mice.

Kihito (KIT; Gui Pi Tang) is a traditional herbal medicine that is used for treatment of neuropsychiatric disorders such as depression, anxiety, neurosis and insomnia in China and Japan. Recently, it has also been shown that KIT improves cognitive dysfunction in patients with Alzheimer's disease. In this study, to investigate the mechanisms underlying the effects of KIT on stress-induced brain dysfunctions such as a depressed state and memory impairment, we examined whether KIT prevents behavioral and neurophysiological abnormalities in mice treated chronically with corticosterone (CORT).

Low folate induces abnormal neuronal maturation and DNA hypomethylation of neuronal differentiation-related genes in cultured mouse neural stem and progenitor cells.

Folate deficiency in a fetus is well known to cause neurodevelopment defects and development disorders. A low level of folate is also thought to be a risk for depression in adults. We have previously shown that post-weaning low folate induces neuronal immaturity in the dentate gyrus in mice, which suggests that low folate causes neuropsychological disorders via inhibition of neuronal maturation.

Ferulic acid alleviates abnormal behaviors in isolation-reared mice via 5-HT receptor partial agonist activity.

Rationale: Preclinical and clinical reports suggest that ferulic acid (FA), a plant-derived phenylpropanoid, is effective against mental health problems such as agitation, anxiety, and irritability in humans, without causing adverse side effects. However, the mechanism of action is unknown.

Objective: The aim of the study is to investigate the mechanism underlying the ameliorative effects of FA on mental health problems such as agitation, anxiety, and irritability, using in vivo behavioral analysis, in vitro pharmacological analysis, and in silico binding analysis.

Adenovirus vector-based incorporation of a photo-cross-linkable amino acid into proteins in human primary cells and cancerous cell lines.

The site-specific incorporation of cross-linkable designer amino acids into proteins is useful for covalently bonding protein complexes upon exposure to light. This technology can be used to study networks of protein-protein interactions in living cells; however, to date it has only been applicable for use with a narrow range of cell types, due to the limited availability of plasmid-based transfection protocols. In the present study, we achieved adenovirus-based expression of a variant of an archaeal pyrrolysyl-tRNA synthetase and UAG-recognising tRNA pair, which was used to incorporate unnatural amino acids into proteins at sites defined by in-frame UAG codons within genes.