GABA function in mood disorders: an update and critical review

A review: oligodendrocytes in neuronal axonal conduction and methods for enhancing their performance

OBJECTIVES

This review explores the vital role of oligodendrocytes in axon myelination and efficient neuronal transmission and the impact of dysfunction resulting from neurotransmitter deficiencies related disorders. Furthermore, the review also provides insight into the potential of bionanotechnology for addressing neurodegenerative diseases by targeting oligodendrocytes.

METHODS

A review of literature in the field was conducted using Google scholar. Systematic searches were performed to identify relevant studies and reviews addressing the role of oligodendrocytes in neural function, the influence of neurotransmitters on oligodendrocyte differentiation, and the potential of nanotechnology-based strategies for targeted therapy of oligodendrocytes.

RESULTS

This review indicates the mechanisms underlying oligodendrocyte differentiation and the influence of neurotransmitters on this process. The importance of action potentials and neurotransmission in neural function and the susceptibility of damaged nerve axons to ischemic or toxic damage is provided in detail. The potential of bionanotechnology for targeting neurodegenerative diseases using nanotechnology-based strategies, including polymeric, lipid-based, inorganic, organic, and biomimetic nanoparticles, suggests better management of neurodegenerative disorders.

CONCLUSION

While nanotechnology-based biomaterials show promise for targeted oligodendrocyte therapy in addressing neurodegenerative disorders linked to oligodendrocyte dysfunction, encapsulating neuroprotective agents within nanoparticles offers additional advantages. Nano-based delivery systems effectively protect drugs from degradation and prolong their therapeutic effects, holding promise in overcoming the blood-brain barrier by facilitating drug transport. However, a multifaceted approach is essential to enhance oligodendrocyte differentiation, promote myelin repair, and facilitate myelin dynamics with reduced toxicity. Further research is needed to elucidate the optimal therapeutic approaches and enhance patient outcomes.

GABA-immunoreactive neurons in the Central Nervous System of the viviparous teleost Poecilia sphenops

Gamma-aminobutyric acid (GABA) functions as the primary inhibitory neurotransmitter within the central nervous system (CNS) of vertebrates. In this study, we examined the distribution pattern of GABA-immunoreactive (GABA-ir) cells and fibres in the CNS of the viviparous teleost Poecilia sphenops using immunofluorescence method. GABA immunoreactivity was seen in the glomerular, mitral, and granular layers of the olfactory bulbs, as well as in most parts of the dorsal and ventral telencephalon. The preoptic area consisted of a small cluster of GABA-ir cells, whereas extensively labelled GABA-ir neurons were observed in the hypothalamic areas, including the paraventricular organ, tuberal hypothalamus, nucleus recessus lateralis, nucleus recessus posterioris, and inferior lobes. In the thalamus, GABA-positive neurons were only found in the ventral thalamic and central posterior thalamic nuclei, whereas the dorsal part of the nucleus pretectalis periventricularis consisted of a few GABA-ir cells. GABA-immunoreactivity was extensively seen in the alar and basal subdivisions of the midbrain, whereas in the rhombencephalon, GABA-ir cells and fibres were found in the cerebellum, motor nucleus of glossopharyngeal and vagal nerves, nucleus commissuralis of Cajal, and reticular formation. In the spinal cord, GABA-ir cells and fibres were observed in the dorsal horn, ventral horn, and around the central canal. Overall, the extensive distribution of GABA-ir cells and fibres throughout the CNS suggests several roles for GABA, including the neuroendocrine, viscerosensory, and somatosensory functions, for the first time in a viviparous teleost.

Optimization of Nutrient-Rich Ice Plant (Mesembryanthemum crystallinum L.) Paste Fresh Noodle Pasta Using Response Surface Methodology

The ice plant is a species that is grown mainly in the dry regions of the American West and contains various minerals and ingredients beneficial for human health, such as inositol and beta-carotene. With the growing trend towards healthy foods, pasta consumption has also increased. Pasta is a convenient and low-glycemic-index food that is composed mainly of carbohydrates, proteins, lipids, dietary fiber, and trace amounts of minerals. The optimal mixing ratio was evaluated to produce pasta of the highest quality in terms of blood sugar elevation and antioxidant efficacy. The components and minerals of the ice plant, including D-pinitol and inositol, were analyzed, and 20 essential amino acids were identified. In this study, we also investigated the quality and characteristics of ice plant paste and eggs, as well as the quality, antioxidant activity, and formulation of raw materials mixed with ice plant at different ratios. Optimal conditions were found to be 46.73 g of ice plant paste in 100 g of durum wheat flour, 20.23 g of egg, and 2 g of salt, providing a way to develop fresh pasta that enhances the health benefits of ice plant paste without excessive moisture and other ingredients.

Maternal separation in mice leads to anxiety-like/aggressive behavior and increases immunoreactivity for glutamic acid decarboxylase and parvalbumin in the adolescence ventral hippocampus

It has been reported that stressful events in early life influence behavior in adulthood and are associated with different psychiatric disorders, such as major depression, post-traumatic stress disorder, bipolar disorder, and anxiety disorder. Maternal separation (MS) is a representative animal model for reproducing childhood stress. It is used as an animal model for depression, and has well-known effects, such as increasing anxiety behavior and causing abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis. This study investigated the effect of MS on anxiety or aggression-like behavior and the number of GABAergic neurons in the hippocampus. Mice were separated from their dams for four hours per day for 19 d from postnatal day two. Elevated plus maze (EPM) test, resident-intruder (RI) test, and counted glutamic acid decarboxylase 67 (GAD67) or parvalbumin (PV) positive cells in the hippocampus were executed using immunohistochemistry. The maternal segregation group exhibited increased anxiety and aggression in the EPM test and the RI test. GAD67-positive neurons were increased in the hippocampal regions we observed: dentate gyrus (DG), CA3, CA1, subiculum, presubiculum, and parasubiculum. PV-positive neurons were increased in the DG, CA3, presubiculum, and parasubiculum. Consistent with behavioral changes, corticosterone was increased in the MS group, suggesting that the behavioral changes induced by MS were expressed through the effect on the HPA axis. Altogether, MS alters anxiety and aggression levels, possibly through alteration of cytoarchitecture and output of the ventral hippocampus that induces the dysfunction of the HPA axis.

Neuromolecular Etiology of Bipolar Disorder: Possible Therapeutic Targets of Mood Stabilizers

Bipolar disorder is a mental illness that causes extreme mood swings and has a chronic course. However, the mechanism by which mood episodes with completely opposite characteristics appear repeatedly, or a mixture of symptoms appears, in patients with bipolar disorder remains unknown. Therefore, mood stabilizers are indicated only for single mood episodes, such as manic episodes and depressive episodes, and no true mood-stabilizing drugs effective for treating both manic and depressive episodes currently exist. Therefore, in this review, therapeutic targets that facilitate the development of mood stabilizers were examined by reviewing the current understanding of the neuromolecular etiology of bipolar disorder.

Neurobehavioral effects of acute low-dose whole-body irradiation

Radiation exposure has multiple effects on the brain, behavior and cognitive functions. It has been reported that high-dose (>20 Gy) radiation-induced behavior and cognitive aberration partly associated with severe tissue destruction. Low-dose (<3 Gy) exposure can occur in radiological disasters and cerebral endovascular treatment. However, only a few reports analyzed behavior and cognitive functions after low-dose irradiation. This study was undertaken to assess the relationship between brain neurochemistry and behavioral disruption in irradiated mice. The irradiated mice (0.5 Gy, 1 Gy and 3 Gy) were tested for alteration in their normal behavior over 10 days. A serotonin (5-HT), Dopamine, gamma-Aminobutyric acid (GABA) and cortisol analysis was carried out in blood, hippocampus, amygdala and whole brain tissue. There was a significant decline in the exploratory activity of mice exposed to 3 Gy and 1 Gy radiation in an open field test. We observed a significant short-term memory loss in 3 Gy and 1 Gy irradiated mice in Y-Maze. Mice exposed to 1 Gy and 3 Gy radiation exhibited increased anxiety in an elevated plus maze (EPM). The increased anxiety and memory loss patterns were also seen in 0.5 Gy irradiated mice, but the results were not statistically significant. In this study we observed that neurotransmitters are significantly altered after irradiation, but the neuronal cells in the hippocampus were not significantly affected. This study suggests that the low-dose radiation-induced cognitive impairment may be associated with the neurochemical in low-dose irradiation and unlike the high-dose scenario might not be directly related to the morphological changes in the brain.

Analyzing the effect of germination on the pasting, rheological, morphological and in- vitro antioxidant characteristics of kodo millet flour and extracts

The present investigationwas carried out to determine the effect of germination on pasting, rheological, morphological properties of Kodo millet flour and in-vitroantioxidant characteristics of its phenolic and γ-amino butyric acid extracts. Rheological analysis depicted complex flour viscosity decreased with an improvement in shear intensity, symbolizing the shear-thinning action of flour upon germination. The frequency and temperature sweep demonstrated a decrease in visco-elasticity as a result of germination wherein, SEM revealed destruction in the continuous composite structure of starch which got entangled in dense protein matrix following germination. The in-vitroantioxidant activities such as total antioxidant capacity, DPPH*, FRAP, metal chelating ability and hydrogen peroxide scavenging activities of both the extracts increased significantly. There was a decrease in pasting properties and gelatinization behaviour whereas, visco-elastic solid behaviour changed to visco-elastic fluid. This research explores the potential of germinated Kodo millet flour for valuable bioactive compounds extraction and its utilization in product development.

Lithium and GADL1 regulate glycogen synthase kinase-3 activity to modulate KCTD12 expression

Potassium channel tetramerization domain containing 12 (KCTD12), the auxiliary GABA_B receptor subunit, is identified as a susceptibility gene for bipolar I (BPI) disorder in the Han Chinese population. Moreover, the single-nucleotide polymorphism (SNP) rs17026688 in glutamate decarboxylase–like protein 1 (GADL1) is shown to be associated with lithium response in Han Chinese BPI patients. In this study, we demonstrated for the first time the relationship among lithium, GADL1, and KCTD12. In circulating CD11b⁺ macrophage cells, BPI patients showed a significantly higher percentage of KCTD12 expression than healthy controls. Among BPI patients, carriers of the ‘T’ allele (i.e., CT or TT) at site rs17026688 were found to secrete lower amounts of GADL1 but higher amounts of GABA b receptor 2 (GABBR2) in the plasma. In human SH-SY5Y neuroblastoma cells, lithium treatment increased the percentage of KCTD12 expression. Through inhibition of glycogen synthase kinase-3 (GSK-3), lithium induced cyclic AMP-response element binding protein (CREB)–mediated KCTD12 promoter activation. On the other hand, GADL1 overexpression enhanced GSK-3 activation and inhibited KCTD12 expression. We found that lithium induced, whereas GADL1 inhibited, KCTD12 expression. These findings suggested that KCTD12 may be an important gene with respect to neuron excitability and lithium response in BPI patients. Therefore, targeting GSK-3 activity and/or KCTD12 expression may constitute a possible therapeutic strategy for treating patients with BPI disorder.

GABAA receptor subunit expression changes in the human Alzheimer's disease hippocampus, subiculum, entorhinal cortex and superior temporal gyrus

Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. GABA type A receptors (GABA_A Rs) are severely affected in Alzheimer's disease (AD). However, the distribution and subunit composition of GABA_A Rs in the AD brain are not well understood. This is the first comprehensive study to show brain region- and cell layer-specific alterations in the expression of the GABA_A R subunits α1-3, α5, β1-3 and γ2 in the human AD hippocampus, entorhinal cortex and superior temporal gyrus. In late-stage AD tissue samples using immunohistochemistry we found significant alteration of all investigated GABA_A Rs subunits except for α3 and β1 that were well preserved. The most prominent changes include an increase in GABA_A R α1 expression associated with AD in all layers of the CA3 region, in the stratum (str.) granulare and hilus of the dentate gyrus. We found a significant increase in GABA_A R α2 expression in the str. oriens of the CA1-3, str. radiatum of the CA2,3 and decrease in the str. pyramidale of the CA1 region in AD cases. In AD there was a significant increase in GABA_A R α5 subunit expression in str. pyramidale, str. oriens of the CA1 region and decrease in the superior temporal gyrus. We also found a significant decrease in the GABA_A R β3 subunit immunoreactivity in the str. oriens of the CA2, str. granulare and str. moleculare of the dentate gyrus. In conclusion, these findings indicate that the expression of the GABA_A R subunits shows brain region- and layer-specific alterations in AD, and these changes could significantly influence and alter GABA_A R function in the disease. Cover Image for this issue: doi: 10.1111/jnc.14179.

Diversity in protein secondary structure, molecular weight, mineral and amino acid composition of lentil and horse gram germplasm

Lentil and horse gram germplasm was assessed for variety in seed and flour properties. Horsegram grains showed higher a* and b* and lower L* values as compared to lentil grains indicating lentil grains were lighter in color as compared to horse gram. Both the pulses showed significant differential accumulation of minerals. Flours from horse gram lines showed higher Mn, K, Mg, Na, Zn and Ca content and lower Cu and Fe content as compared to lentil lines. Polypeptide of 42 kDa was present in IC94636 and IC139555 only and 35 kDa PP subunit was absent in all the horse gram lines except IC94636. Major polymorphism among lentil lines was observed in 10, 35-37 and 55-49 kDa PP subunits. Amount of β-sheets and β-turns was the highest whereas that of antiparallel β-sheets was the lowest. NIC17550, NIC17551 and NIC17552 showed higher content of antiparallel β-sheets and random coils among lentil lines. PL1 showed the highest portion of α-helixes and β-turns whereas PL57 showed the highest proportion of β-sheets among lentil lines. Lentil flours showed higher proportion of aspartic acid, glutamic acid, asparagine, serine, citrulline and serine and lower proportion of histidine, threonine, GABA, tyrosine and cystine as compared to horse gram.

Stress-Induced Functional Alterations in Amygdala: Implications for Neuropsychiatric Diseases

The amygdala plays a major role in the processing of physiologic and behavioral responses to stress and is characterized by gamma-aminobutyric acid (GABA)-mediated high inhibitory tone under resting state. Human and animal studies showed that stress lead to a hyperactivity of amygdala, which was accompanied by the removal of inhibitory control. However, the contribution of hyperactivity of amygdala to stress-induced neuropsychiatric diseases, such as anxiety and mood disorders, is still dubious. In this review, we will summarize stress-induced various structural and functional alterations in amygdala, including the GABA receptors expression, GABAergic transmission and synaptic plasticity. It may provide new insight on the neuropathologic and neurophysiological mechanisms of neuropsychiatric diseases.

Pathology of nNOS-Expressing GABAergic Neurons in Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of dementia that is often accompanied by mood and emotional disturbances and seizures. There is growing body of evidence that neurons expressing γ-aminobutyric acid (GABA) play an important role in regulation of cognition, mood, and emotion as well as seizure susceptibility, but participation of GABAergic neuronal pathology in Alzheimer's disease (AD) is not understood well at present. Here, we report that transgenic mice expressing human amyloid precursor protein Swedish-Dutch-Iowa mutant (APP_SweDI) exhibit early loss of neurons expressing GAD67, a GABA-synthesizing enzyme, in advance of the loss of pyramidal neurons in hippocampal CA1 region. The loss of GAD67⁺ neurons in APP_SweDI mice accompanied with decreased spatial cognition as well as increased anxiety-like behaviors and kainic acid-induced seizure susceptibility at early phase. In the hippocampal CA1 region, GAD67⁺ neurons expressed high basal levels of neuronal nitric oxide synthase (nNOS) and nitrosative stress (nitrotyrosine). Similarly, GAD67⁺ neurons in primary cortical and hippocampal neuron cultures also expressed high basal levels of nNOS and degenerated in response to lower Aβ concentrations due to their high basal levels of nitrosative stress. Given the role of GABAergic neurons in cognitive and neuropsychiatric functions, this study reports the role of nNOS-mediated nitrosative stress in dysfunction of GABAergic neurons and its potential participation in early development of cognitive and neuropsychiatric symptoms in AD.

Methylene blue and its analogues as antidepressant compounds

Methylene Blue (MB) is considered to have diverse medical applications and is a well-described treatment for methemoglobinemias and ifosfamide-induced encephalopathy. In recent years the focus has shifted to MB as an antimalarial agent and as a potential treatment for neurodegenerative disorders such as Alzheimer's disease. Of interest are reports that MB possesses antidepressant and anxiolytic activity in pre-clinical models and has shown promise in clinical trials for schizophrenia and bipolar disorder. MB is a noteworthy inhibitor of monoamine oxidase A (MAO-A), which is a well-established target for antidepressant action. MB is also recognized as a non-selective inhibitor of nitric oxide synthase (NOS) and guanylate cyclase. Dysfunction of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) cascade is strongly linked to the neurobiology of mood, anxiety and psychosis, while the inhibition of NOS and/or guanylate cyclase has been associated with an antidepressant response. This action of MB may contribute significantly to its psychotropic activity. However, these disorders are also characterised by mitochondrial dysfunction and redox imbalance. By acting as an alternative electron acceptor/donor MB restores mitochondrial function, improves neuronal energy production and inhibits the formation of superoxide, effects that also may contribute to its therapeutic activity. Using MB in depression co-morbid with neurodegenerative disorders, like Alzheimer's and Parkinson's disease, also represents a particularly relevant strategy. By considering their physicochemical and pharmacokinetic properties, analogues of MB may provide therapeutic potential as novel multi-target strategies in the treatment of depression. In addition, low MAO-A active analogues may provide equal or improved response with a lower risk of adverse effects.

Effects of Psychotropic Drugs on Seizure Threshold during Electroconvulsive Therapy

OBJECTIVE

To analyze the relationship between seizure threshold (ST) and psychotropic drugs in patients treated with ECT.

METHODS

We examined clinical data from 43 patients. ST was titrated at each treatment session. We examined associations between ST and psychotropic drugs using multivariate correlation analyses. Data are presented as initial ST, the difference in ST between the first and 10th sessions (ΔST_10th), and the mean difference in ST between the first and last sessions (mean ΔST_last).

RESULTS

Multivariate regression analyses showed associations between initial ST and the total chlorpromazine-equivalent dose of antipsychotics (β=0.363, p<0.05). The total fluoxetine-equivalent dose of antidepressants was associated with ΔST_10th (β=0.486, p<0.01) and mean ΔST_last (β=0.472, p<0.01).

CONCLUSION

Our study elucidated possible effects of psychotropic drugs on ST shifts. Larger doses of antipsychotics were associated with higher initial ST, whereas higher doses of antidepressants were associated with stronger shifts in ST.

Using combined optimization, GC-MS and analytical technique to analyze the germination effect on phenolics, dietary fibers, minerals and GABA contents of Kodo millet (Paspalum scrobiculatum)

A central composite rotatable design was applied to study the effects of soaking time, germination time and temperature on the responses; total phenolics, total flavonoids and antioxidant activity for the biochemical enhancement of bioactive components of Kodo millet. The optimum conditions for producing germinated Kodo millet flour of highest TPC (83.01mgGAE/100g), TFC (87.53mgRUE/g) and AoxA (91.34%), were soaking time (13.81h), germination temperature (38.75°C) and germination time (35.82h). Protein increased significantly form, 6.7 to 7.9%, dietary fibers from 35.30 to 38.34g/100g, minerals from 232.82 to 251.73mg/100g, GABA contents from 9.36 to 47.43mg/100g, whereas phytates and tannins decreased from 1.344 to 0.997mol/kg and 1.603 to 0.234mg/100g respectively, in optimized germinated Kodo millet sample. Six new bioactive compounds [n-propyl-9,12,15-octadecatrienoate (0.86%), pregan,20-one-2hydroxy,5,6,epox-15-methyl (3.45%), hexa-decanoicacid (8.19%), 9,O-ctadecenoicacid (5.00%), butyl-6,9,12,15-octadecatetraenoate (4.03%), hexadecanoicacid-methylester (1.43%)], synthesized as a result of germination under optimum conditions in the Kodo millet depicted the germination potential of millets as a source of valuable bioactive compounds.

Anticonvulsant activity of an active fraction extracted from Crinum jagus L. (Amaryllidaceae), and its possible effects on fully kindled seizures, depression-like behaviour and oxidative stress in experimental rodent models

ETHNOPHARMACOLOGICAL RELEVANCE

The leaf extract of Crinum jagus L. (Amaryllidaceae) is widely used in traditional Cameroonian medicine as antiepileptic remedy and for the treatment of convulsion, depression and mood disorders associated with epilepsy.

AIM OF THE STUDY

Hence, this study was conducted to evaluate the effects of an active fraction extracted from the leaves of Crinum jagus against seizures, depression-like behaviour and oxidative stress in pentylenetetrazole (PTZ)-induced kindling in mice.

MATERIALS AND METHODS

Bioactive-guided fractionation of the leaf extract of Crinum jagus by using 70mg/kg PTZ-induced convulsions in mice, afforded a potent anticonvulsant fraction (flavonol kaempferol; C4.4). The effects of C4.4 on 30mg/kg PTZ-induced kindling, kindling-induced depression like-behaviour and oxidative stress was evaluated. Mice were injected PTZ (30mg/kg, i.p.) once every alternate day (48±1h) until the development of kindling. Depression was assessed using tail suspension test and forced swim test while the oxidative stress parameters were estimated in the whole brain at the end of experiments. Mice were submitted to the rota-rod task and open-field test in order to assess any non-specific muscle-relaxant or sedative effects of C4.4. Acute toxicity of C4.4 was also assessed in mice.

RESULTS

Convulsions-induced by 70mg/kg PTZ were strongly antagonized by C4.4. Oral administration of C4.4 significantly increased the latency to myoclonic jerks, clonic seizures as well as generalized tonic-clonic seizures, improved the seizure mean stage and decreased the number of myoclonic jerks in PTZ-kindled mice. The data indicated also that C4.4 significantly reduced the immobility times in the tail suspension test and the forced swim test. This active fraction has also antioxidant properties by decreasing the lipid peroxidation, and augmenting endogenous antioxidant enzymes in brain. C4.4 administered (12.5-50mg/kg) did not alter the locomotion of animals in the open-field or rotarod tests, which suggest a lack of a central depressant effect. The animals did not exhibit any acute toxicity to C4.4 at the therapeutic doses.

CONCLUSION

These results suggest that pretreatment with C4.4 ameliorates convulsions-induced by PTZ, protects mice against kindling development, depression-like behaviour and oxidative stress in PTZ-kindled mice. These finding provides scientific rationale for the use of Crinum jagus extracts for the amelioration of epilepsy observed in traditional medicine in Cameroon.

Isolation of Functional Components β-Glucan and γ-Amino Butyric Acid from Raw and Germinated Barnyard Millet (Echinochloa frumentaceae) and their Characterization

The study was carried out to analyze the characteristics of two functional constituents' viz. γ-amino butyric acid (GABA) and β-glucan extracted from raw and germination barnyard millet (var. PRJ-1). A significant (P ≤ 0.05) effect of germination (sprouting) was observed in yield, chemical composition, functional, rheological and antioxidant properties of β-glucan and GABA. The yield of GABA extract was 12.34 % and the content increased from 6.37 mg/100 g in raw to 35.70 mg/100 g in germinated sample. The DPPH, total antioxidant and hydrogen peroxide scavenging activities of GABA extract increased after germination from 45.34 to 65.34 %, 15.3 to 33.3 millimole/g and 38.4 to 64.7 millimole/g, respectively. The yield of β-glucan extract of raw and germinated flour was 6.05 and 5.01 % whereas the β-glucan contents were 83.30 and 79.64 %, respectively. The functional properties of β-glucan i.e., swelling power, water binding capacity and DPPH scavenging activity increased from 1.45 to 1.76 g/g, 2.13 to 2.32 g/g and 44.39 to 57.42 %, respectively, after germination. Similarly there was an increase in the storage modulus after germination process which attributes a better viscoelastic capacity of β-glucan at low frequencies. The results exploit that the β-glucan and GABA might promise a polymeric incipient to be implemented as food additives with variable functional and structural characteristics.

Acceptability, Safety, and Efficacy of Oral Administration of Extracts of Black or Red Maca (Lepidium meyenii) in Adult Human Subjects: A Randomized, Double-Blind, Placebo-Controlled Study

The plant maca, grown at 4000 m altitude in the Peruvian Central Andes, contains hypocotyls that have been used as food and in traditional medicine for centuries. The aim of this research was to provide results on some health effects of oral administration of spray-dried extracts of black or red maca (Lepidium meyenii) in adult human subjects living at low (LA) and high altitude (HA). A total of 175 participants were given 3 g of either placebo, black, or red maca extract daily for 12 weeks. Primary outcomes were changes in sexual desire, mood, energy, health-related quality of life score (HRQL), and chronic mountain sickness (CMS) score, or in glycaemia, blood pressure, and hemoglobin levels. Secondary outcomes were acceptability and safety, assessed using the Likert test and side effect self-recording, respectively, and the effect of altitude. At low altitude, 32, 30, and 32 participants started the study receiving placebo, red maca, or black maca, respectively. At high altitudes, 33, 35, and 31 participants started the study receiving placebo, red maca, and black maca, respectively. Consumption of spray-dried extracts of red and black maca resulted in improvement in mood, energy, and health status, and reduced CMS score. Fatty acids and macamides were higher in spray-dried extracts of black maca than in red maca. GABA predominated in spray-dried extracts of red maca. Effects on mood, energy, and CMS score were better with red maca. Black maca and, in smaller proportions, red maca reduced hemoglobin levels only in highlanders with abnormally high hemoglobin levels; neither variety of maca reduced hemoglobin levels in lowlanders. Black maca reduced blood glucose levels. Both varieties produced similar responses in mood, and HRQL score. Maca extracts consumed at LA or HA had good acceptability and did not show serious adverse effects. In conclusion, maca extract consumption relative to the placebo improved quality of life parameters. Differences in the level of improvement between red and black maca are probably due to differences in the composition of these two plant varieties. Both maca extracts were well tolerated and safe.

An update of the classical and novel methods used for measuring fast neurotransmitters during normal and brain altered function

To understand better the cerebral functions, several methods have been developed to study the brain activity, they could be related with morphological, electrophysiological, molecular and neurochemical techniques. Monitoring neurotransmitter concentration is a key role to know better how the brain works during normal or pathological conditions, as well as for studying the changes in neurotransmitter concentration with the use of several drugs that could affect or reestablish the normal brain activity. Immediate response of the brain to environmental conditions is related with the release of the fast acting neurotransmission by glutamate (Glu), γ-aminobutyric acid (GABA) and acetylcholine (ACh) through the opening of ligand-operated ion channels. Neurotransmitter release is mainly determined by the classical microdialysis technique, this is generally coupled to high performance liquid chromatography (HPLC). Detection of neurotransmitters can be done by fluorescence, optical density, electrochemistry or other detection systems more sophisticated. Although the microdialysis method is the golden technique to monitor the brain neurotransmitters, it has a poor temporal resolution. Recently, with the use of biosensor the drawback of temporal resolution has been improved considerably, however other inconveniences have merged, such as stability, reproducibility and the lack of reliable biosensors mainly for GABA. The aim of this review is to show the important advances in the different ways to measure neurotransmitter concentrations; both with the use of classic techniques as well as with the novel methods and alternant approaches to improve the temporal resolution.

Long-term behavioral programming induced by peripuberty stress in rats is accompanied by GABAergic-related alterations in the Amygdala

Stress during childhood and adolescence is a risk factor for psychopathology. Alterations in γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain, have been found following stress exposure and fear experiences and are often implicated in anxiety and mood disorders. Abnormal amygdala functioning has also been detected following stress exposure and is also implicated in anxiety and social disorders. However, the amygdala is not a unitary structure; it includes several nuclei with different functions and little is known on the potential differences the impact of early life stress may have on this system within different amygdaloid nuclei. We aimed here to evaluate potential regional differences in the expression of GABAergic-related markers across several amygdaloid nuclei in adult rats subjected to a peripuberty stress protocol that leads to enhanced basal amygdala activity and psychopathological behaviors. More specifically, we investigated the protein expression levels of glutamic acid decarboxylase (GAD; the principal synthesizing enzyme of GABA) and of GABA-A receptor subunits α2 and α3. We found reduced GAD and GABA-A α3, but not α2, subunit protein levels throughout all the amygdala nuclei examined (lateral, basolateral, basomedial, medial and central) and increased anxiety-like behaviors and reduced sociability in peripubertally stressed animals. Our results identify an enduring inhibition of the GABAergic system across the amygdala following exposure to early adversity. They also highlight the suitability of the peripuberty stress model to investigate the link between treatments targeting the dysfunctional GABAergic system in specific amygdala nuclei and recovery of specific stress-induced behavioral dysfunctions.

The need for a comprehensive molecular characterization of autism spectrum disorders

Autism spectrum disorders (ASD) are a heterogeneous group of disorders which have complex behavioural phenotypes. Although ASD is a highly heritable neuropsychiatric disorder, genetic research alone has not provided a profound understanding of the underlying causes. Recent developments using biochemical tools such as transcriptomics, proteomics and cellular models, will pave the way to gain new insights into the underlying pathological pathways. This review addresses the state-of-the-art in the search for molecular biomarkers for ASD. In particular, the most important findings in the biochemical field are highlighted and the need for establishing streamlined interaction between behavioural studies, genetics and proteomics is stressed. Eventually, these approaches will lead to suitable translational ASD models and, therefore, a better disease understanding which may facilitate novel drug discovery efforts in this challenging field.

Neurobiological effects of the green tea constituent theanine and its potential role in the treatment of psychiatric and neurodegenerative disorders

Theanine (n-ethylglutamic acid), a non-proteinaceous amino acid component of green and black teas, has received growing attention in recent years due to its reported effects on the central nervous system. It readily crosses the blood-brain barrier where it exerts a variety of neurophysiological and pharmacological effects. Its most well-documented effect has been its apparent anxiolytic and calming effect due to its up-regulation of inhibitory neurotransmitters and possible modulation of serotonin and dopamine in selected areas. It has also recently been shown to increase levels of brain-derived neurotrophic factor. An increasing number of studies demonstrate a neuroprotective effects following cerebral infarct and injury, although the exact molecular mechanisms remain to be fully elucidated. Theanine also elicits improvements in cognitive function including learning and memory, in human and animal studies, possibly via a decrease in NMDA-dependent CA1 long-term potentiation (LTP) and increase in NMDA-independent CA1-LTP. Furthermore, theanine administration elicits selective changes in alpha brain wave activity with concomitant increases in selective attention during the execution of mental tasks. Emerging studies also demonstrate a promising role for theanine in augmentation therapy for schizophrenia, while animal models of depression report positive improvements following theanine administration. A handful of studies are beginning to examine a putative role in attention deficit hyperactivity disorder, and theoretical extrapolations to a therapeutic role for theanine in other psychiatric disorders such as anxiety disorders, panic disorder, obsessive compulsive disorder (OCD), and bipolar disorder are discussed.

Time-dependent changes of calbindin D-28K and parvalbumin immunoreactivity in the hippocampus of rats with streptozotocin-induced type 1 diabetes

The hippocampus is affected by various stimuli that include hyperglycemia, depression, and ischemia. Calcium-binding proteins (CaBPs) have protective roles in the response to such stimuli. However, little is known about the expression of CaBPs under diabetic conditions. This study was conducted to examine alterations in the physiological parameters with type 1 diabetes induced with streptozotocin (STZ) as well as time-dependent changes in the expression of two CaBPs changes of were being evaluated. Rats treated with STZ (70 mg/kg) had high blood glucose levels (>21.4 mmol/L) along with increased food intake and water consumption volumes compared to the sham controls. In contrast, body weight of the animals treated with STZ was significantly reduced compared to the sham group. CB-specific immunoreactivity was generally increased in the hippocampal CA1 region and granule cell layer of the dentate gyrus (DG) 2 weeks after STZ treatment, but decreased thereafter in these regions. In contrast, the number of PV-immunoreactive neurons and fibers was unchanged in the hippocampus and DG 2 weeks after STZ treatment. However, this number subsequently decreased over time. These results suggest that CB and PV expression is lowest 3 weeks after STZ administration, and these deficits lead to disturbances in calcium homeostasis.

Potential mechanisms of action of lithium in bipolar disorder. Current understanding

Lithium has been used for over half a century for the treatment of bipolar disorder as the archetypal mood stabilizer, and has a wealth of empirical evidence supporting its efficacy in this role. Despite this, the specific mechanisms by which lithium exerts its mood-stabilizing effects are not well understood. Given the inherently complex nature of the pathophysiology of bipolar disorder, this paper aims to capture what is known about the actions of lithium ranging from macroscopic changes in mood, cognition and brain structure, to its effects at the microscopic level on neurotransmission and intracellular and molecular pathways. A comprehensive literature search of databases including MEDLINE, EMBASE and PsycINFO was conducted using relevant keywords and the findings from the literature were then reviewed and synthesized. Numerous studies report that lithium is effective in the treatment of acute mania and for the long-term maintenance of mood and prophylaxis; in comparison, evidence for its efficacy in depression is modest. However, lithium possesses unique anti-suicidal properties that set it apart from other agents. With respect to cognition, studies suggest that lithium may reduce cognitive decline in patients; however, these findings require further investigation using both neuropsychological and functional neuroimaging probes. Interestingly, lithium appears to preserve or increase the volume of brain structures involved in emotional regulation such as the prefrontal cortex, hippocampus and amygdala, possibly reflecting its neuroprotective effects. At a neuronal level, lithium reduces excitatory (dopamine and glutamate) but increases inhibitory (GABA) neurotransmission; however, these broad effects are underpinned by complex neurotransmitter systems that strive to achieve homeostasis by way of compensatory changes. For example, at an intracellular and molecular level, lithium targets second-messenger systems that further modulate neurotransmission. For instance, the effects of lithium on the adenyl cyclase and phospho-inositide pathways, as well as protein kinase C, may serve to dampen excessive excitatory neurotransmission. In addition to these many putative mechanisms, it has also been proposed that the neuroprotective effects of lithium are key to its therapeutic actions. In this regard, lithium has been shown to reduce the oxidative stress that occurs with multiple episodes of mania and depression. Further, it increases protective proteins such as brain-derived neurotrophic factor and B-cell lymphoma 2, and reduces apoptotic processes through inhibition of glycogen synthase kinase 3 and autophagy. Overall, it is clear that the processes which underpin the therapeutic actions of lithium are sophisticated and most likely inter-related.

Opioid system and Alzheimer's disease

The opioid system may be involved in the pathogenesis of AD, including cognitive impairment, hyperphosphorylated tau, Aβ production, and neuroinflammation. Opioid receptors influence the regulation of neurotransmitters such as acetylcholine, norepinephrine, GABA, glutamate, and serotonin which have been implicated in the pathogenesis of AD. Opioid system has a close relation with Aβ generation since dysfunction of opioid receptors retards the endocytosis and degradation of BACE1 and γ-secretase and upregulates BACE1 and γ-secretase, and subsequently, the production of Aβ. Conversely, activation of opioid receptors increases the endocytosis of BACE1 and γ-secretase and downregulates BACE1 and γ-secretase, limiting the production of Aβ. The dysfunction of opioid system (opioid receptors and opioid peptides) may contribute to hyperphosphorylation of tau and neuroinflammation, and accounts for the degeneration of cholinergic neurons and cognitive impairment. Thus, the opioid system is potentially related to AD pathology and may be a very attractive drug target for novel pharmacotherapies of AD.

The Effects of a Gentle Yoga Program on Sleep, Mood, and Blood Pressure in Older Women with Restless Legs Syndrome (RLS): A Preliminary Randomized Controlled Trial

Objective. To examine the effects of yoga versus an educational film program on sleep, mood, perceived stress, and sympathetic activation in older women with RLS. Methods. Participants were drawn from a larger trial regarding the effects of yoga on cardiovascular disease risk profiles in overweight, sedentary postmenopausal women. Seventy-five women were randomized to receive either an 8-week yoga (n = 38) or educational film (n = 37) program. All 75 participants completed an RLS screening questionnaire. The 20 women who met all four diagnostic criteria for RLS (n = 10 yoga, 10 film group) comprised the population for this nested study. Main outcomes assessed pre- and post-treatment included: sleep (Pittsburgh Sleep Quality Index), stress (Perceived Stress Scale), mood (Profile of Mood States, State-Trait Anxiety Inventory), blood pressure, and heart rate. Results. The yoga group demonstrated significantly greater improvements than controls in multiple domains of sleep quality and mood, and significantly greater reductions in insomnia prevalence, anxiety, perceived stress, and blood pressure (all P's≤0.05). Adjusted intergroup effect sizes for psychosocial variables were large, ranging from 1.9 for state anxiety to 2.6 for sleep quality. Conclusions. These preliminary findings suggest yoga may offer an effective intervention for improving sleep, mood, perceived stress, and blood pressure in older women with RLS.

Thymoquinone produced antianxiety-like effects in mice through modulation of GABA and NO levels

The aim of the present study was to investigate the role of GABAergic and nitriergic modulation in the antianxiety effect of thymoquinone, a major constituent of Nigella sativa, in mice under unstressed and stressed conditions. Thymoquinone (10 and 20 mg/kg), methylene blue (1 mg/kg) and diazepam (2 mg/kg) were administered followed by behavioral testing using an elevated plus maze, the light/dark test and the social interaction test in both unstressed and stressed mice (mice subjected to 6 h immobilization). The effects of the above-mentioned drugs on plasma nitrite, a stable metabolite of nitric oxide (NO) and brain GABA content were also studied. Diazepam (2 mg/kg) produced significant anxiolytic-like effects only in unstressed mice. However, diazepam significantly increased the GABA content in both unstressed and stressed mice as compared with their respective control groups. Thymoquinone (10 and 20 mg/kg) produced significant antianxiety effects in unstressed mice without altering nitrite levels, but only the higher dose (20 mg/kg) of thymoquinone increased the GABA content in unstressed mice. In stressed mice, thymoquinone (20 mg/kg) showed anxiolytic effects, with a significant decrease in plasma nitrite and reversal of the decreased brain GABA content. Pre-treatment with methylene blue enhanced the antianxiety effect of thymoquinone in both unstressed and stressed mice. Therefore, the present study suggests an involvement of NO-cGMP and GABAergic pathways in the anxiolytic-like activity of thymoquinone.

Stiff-person syndrome presenting as eating disorder: a case report

OBJECTIVE

To report a case of a 35-year-old female initially treated for anorexia nervosa who was found to have Stiff-Person Syndrome (SPS).

METHOD

Case report.

RESULTS

The patient reported panic attacks at meal times that were found to consist of tetanic contractions of the axial musculature. Swallowing initiated reflexive painful muscle spasms that consequently resulted in cibophobia and significant weight loss. Her serum tested positive for anti-glutamic acid decarboxylase antibodies, and she subsequently improved with appropriate treatment for SPS.

DISCUSSION

SPS has not been previously reported in the context of eating disorders, although it has been linked to other psychiatric disorders. Often the psychiatrist may be the first physician to diagnose SPS. We present this case to alert practitioners to the potential co-morbidity and symptom overlap between SPS and eating disorders, to aid in early recognition and appropriate treatment of this rare illness.

Antidepressant and anxiolytic effects of selective 5-HT6 receptor agonists in rats

RATIONALE

Although selective serotonin reuptake inhibitors (SSRIs) produce clinical therapeutic effects on depression and anxiety through augmentation of serotonergic neurotransmission, there is little known about the potential contributions of the 5-HT(6) receptor in the treatment of mood disorders.

OBJECTIVES

The aim of this study was to test the potential antidepressant-like and anxiolytic-like effects of the 5-HT(6) receptor agonists WAY-208466 and WAY-181187 using established behavioral tests in rats.

METHODS

In order to determine if the 5-HT(6) receptor agonists possess antidepressant-like activity, rats were treated with WAY-208466 or WAY-181187 and tested in the modified rat forced swim test (FST). Also, the potential anxiolytic-like effects of WAY-208466 and WAY-181187 were measured using the defensive burying (DB) test and novelty-induced hypophagia (NIH) test.

RESULTS

WAY-208466 and WAY-181187 produced both antidepressant-like and anxiolytic-like effects. Both compounds decreased immobility and increased swimming behavior in the FST. The effects of the 5-HT(6) receptor agonists were similar to those seen after treatment with the SSRI fluoxetine. Both 5-HT(6) receptor agonists also decreased burying duration in the DB test, indicative of anxiolytic activity in the test. The anxiolytic effects of WAY-208466 were reproduced in the NIH test. Assessment of the anxiolytic effects of WAY-181187 in the NIH was confounded by alterations in home cage feeding behavior.

CONCLUSIONS

These findings suggest that 5-HT(6) receptor agonists may represent a new class of potential antidepressant and anxiolytic compounds and could possess a number of advantages over currently available treatments, including rapid onset of anxiolytic efficacy.

Differential gene expression in a rat model of depression based on persistent differences in exploratory activity

Affective disorders are often accompanied by changes in motivation and anxiety. We investigated the genome-wide gene expression patterns in an animal model of depression that separates Wistar rats belonging into clusters of persistently high anxiety/low motivation to explore and low anxiety/high motivation to explore (low explorers and high explorers, LE and HE, respectively), in three brain regions previously implicated in mood disorders (raphe, hippocampus and the frontal cortex). Several serotonin-, GABA-, and glutamatergic genes were differentially expressed in LE- and HE-rats. The analysis of Gene Ontology biological process terms associated with the differentially regulated genes identified a significant overrepresentation of genes involved in the neuron development, morphogenesis, and differentiation; the most enriched pathways from the Kyoto Encyclopedia of Genes and Genomes were the Wnt signalling, MAPK signalling, long-term potentiation, and long-term depression pathways. These findings corroborate some expression data from other models of depression, and suggest additional targets.

Single prolonged stress: toward an animal model of posttraumatic stress disorder

Although selective serotonin reuptake inhibitors (SSRIs) are reported to be effective in decreasing posttraumatic stress disorder (PTSD) symptoms, a subgroup of PTSD patients remain chronically symptomatic and maintain conditioned fear responses to traumatic stimuli. In this context, the establishment of an appropriate animal model of PTSD is necessary to promote better understanding of the mechanisms of the disorder and to facilitate the development of more effective therapeutic alternatives to SSRIs. Although no single widely accepted animal model of PTSD has been established to date, the single prolonged stress (SPS) animal model has been partially validated as a model for PTSD. SPS rats mimic the pathophysiological abnormalities and behavioral characteristics of PTSD, such as enhanced anxiety-like behavior and glucocorticoid negative feedback, and they exhibit the expected therapeutic response to paroxetine on enhanced fear memory. In addition, SPS rats exhibit enhanced freezing in response to contextual fear conditioning, and impaired extinction of fear memory, which is alleviated by D-cycloserine. The enhanced consolidation and impaired extinction of fear memory found in SPS rats suggests that this model has additional value because recent studies of PTSD indicate that memory abnormalities are a central feature. In this study, we summarize the behavioral and pathophysiological PTSD-like symptoms in SPS, focusing on memory abnormalities, and evaluate the validity of SPS as an animal model of PTSD.

Enhanced visual motion perception in major depressive disorder

Major depressive disorder (MDD) is a mood disorder that is not traditionally considered to affect the visual system. However, recent findings have reported decreased cortical levels of the inhibitory neurotransmitter GABA in occipital cortex. To explore possible functional consequences of MDD on visual processing, we applied a psychophysical visual motion processing task in which healthy young adults typically exhibit impaired perceptual discrimination of large high-contrast stimuli. It has been suggested that this phenomenon, spatial suppression, is mediated by GABAergic center-surround antagonism in visual pathways. Based on previous findings linking MDD to occipital GABA dysfunction, we hypothesized that MDD patients would exhibit decreased spatial suppression, leading to the counterintuitive hypothesis of better psychophysical performance. Indeed, motion perception for typically suppressed stimuli was enhanced in patients with MDD compared with age-matched controls. Furthermore, the degree of spatial suppression correlated with an individual's illness load; patients with greater lifetime duration of depression exhibited the least spatial suppression and performed the best in the high-contrast motion discrimination task. Notably, this decrease in spatial suppression persisted beyond recovery and without the confound of acute illness or treatment; all patients had been clinically recovered and unmedicated for several months at the time of testing, suggesting that depression has ubiquitous consequences that may persist long after mood symptoms have receded. This finding raises the possibility that spatial suppression may represent a sensitive endophenotypic marker of trait vulnerability in MDD.

Use of benzodiazepines, depressive symptoms and cognitive function in old age

OBJECTIVE

Benzodiazepine use is more frequently observed in depressive and cognitively impaired subjects. The temporal relation behind this association is unknown. Here, we studied whether benzodiazepine use is associated with depressive symptoms and cognitive function and what the temporal relation underlying the associations is.

METHODS

Within the Leiden 85-plus Study, a prospective population based study of 599 subjects aged 85 years at baseline, we assessed benzodiazepine use, depressive symptoms, and cognitive function annually during a 5-year follow-up period.

RESULTS

Benzodiazepine users were more likely to be female, be institutionalized, and have a low education. Benzodiazepine users scored 0.76 points higher on the 15-item Geriatric Depression Scale than non-users (95% CI: 0.27-1.25, p = 0.002). They were 1.6-fold more likely to develop new depressive symptoms in 1 year when compared to non-users (95% CI: 1.05-2.55, p = 0.028). Benzodiazepine use did not associate with cognitive function, but discontinued benzodiazepine users had a 4.0 points lower Mini Mental State Examination (MMSE) score in the year before discontinuation than continued benzodiazepine users (95% CI: 1.31-6.73, p = 0.004).

CONCLUSIONS

In old age the use of benzodiazepines is associated with depressive symptoms and the use of benzodiazepines may precede the development of depressive symptoms. Treating physicians seem to be aware of the detrimental effects of benzodiazepines on cognitive function. However, they should be cautious in prescribing a new benzodiazepine in old age and monitor elderly benzodiazepine users for development of depressive symptoms.

The effects of electroconvulsive therapy on GABAergic function in major depressive patients

OBJECTIVES

It has been proposed that major depression is associated with a dysfunction of the gamma-aminobutyric acid (GABA) system. This study was planned to investigate whether there are any alterations in GABAergic activities in major depressive patients and, if there are, whether electroconvulsive therapy (ECT) has any effect on these changes.

METHODS

Twenty-five depressed inpatients who responded to a course of ECT and 23 healthy subjects were included in the study. Serum GABA levels were measured 2 days before and 10 minutes after the first ECT and 3 days after the last ECT, and a baclofen challenge test was performed 2 days before the first ECT and 3 days after the last ECT in the patients. The same tests were carried out only once in the control group.

RESULTS

Depressive patients had lower serum GABA levels compared with healthy individuals, and ECT caused a significant increase in these levels. The acute effect of the one-ECT procedure was a huge increase in the baseline GABA levels. Although there was no difference in the maximum alteration in growth hormone with baclofen between the patients and controls before the therapeutic ECT course, it became significantly higher in the depressive patients than in the controls after the treatment.

CONCLUSIONS

The findings of this study support the GABA deficit hypothesis of major depression because major depressive patients have lower levels of serum GABA that are increased by a completed ECT course. ECT seems to increase brain GABA levels as well as GABAB activity, and these effects may contribute to its mechanism of therapeutic effect.

Is major depressive disorder a metabolic encephalopathy?

Metabolic encephalopathy is an acute disturbance in cellular metabolism in the brain evoked by conditions of hypoxia, hypoglycaemia, oxidative stress and/or inflammation. It usually develops acutely or subacutely and is reversible if the systemic disorder is treated. If left untreated, however, metabolic encephalopathy may result in secondary structural damage to the brain. Most encephalopathies are present with neuropsychiatric symptoms, one in particular being depression. However, mood disorders are often co-morbid with cardiovascular, liver, kidney and endocrine disorders, while increasing evidence concurs that depression involves inflammatory and neurodegenerative processes. This would suggest that metabolic disturbances resembling encephalopathy may underscore the basic neuropathology of depression at a far deeper level than currently realized. Viewing depression as a form of encephalopathy, and exploiting knowledge gleaned from our understanding of the neurochemistry and treatment of metabolic encephalopathy, may assist in our understanding of the neurobiology of depression, but also in realizing new ideas in the pharmacotherapy of mood disorders.

Neuropharmacological profile of novel and selective 5-HT6 receptor agonists: WAY-181187 and WAY-208466

One of the most recently identified serotonin (5-hydroxytryptamine (5-HT)) receptor subtypes is the 5-HT6 receptor. Although in-depth localization studies reveal an exclusive distribution of 5-HT6 mRNA in the central nervous system, the precise biological role of this receptor still remains unknown. In the present series of experiments, we report the pharmacological and neurochemical characterization of two novel and selective 5-HT6 receptor agonists. WAY-181187 and WAY-208466 possess high affinity binding (2.2 and 4.8 nM, respectively) at the human 5-HT6 receptor and profile as full receptor agonists (WAY-181187: EC50=6.6 nM, Emax=93%; WAY-208466: EC50=7.3 nM; Emax=100%). In the rat frontal cortex, acute administration of WAY-181187 (3-30 mg/kg, subcutaneous (s.c.)) significantly increased extracellular GABA concentrations without altering the levels of glutamate or norepinephrine. Additionally, WAY-181187 (30 mg/kg, s.c.) produced modest yet significant decreases in cortical dopamine and 5-HT levels. Subsequent studies showed that the neurochemical effects of WAY-181187 in the frontal cortex could be blocked by pretreatment with the 5-HT6 antagonist, SB-271046 (10 mg/kg, s.c.), implicating 5-HT6 receptor mechanisms in mediating these responses. Moreover, the effects of WAY-181187 on catecholamines were attenuated by an intracortical infusion of the GABA A receptor antagonist, bicuculline (10 microM), confirming a local relationship between 5-HT6 receptors and GABAergic systems in the frontal cortex. In the dorsal hippocampus, striatum, and amygdala, WAY-181187 (10-30 mg/kg, s.c.) elicited robust elevations in extracellular levels of GABA without producing similar effects on concentrations of norepinephrine, serotonin, dopamine, or glutamate. In contrast to these brain regions, WAY-181187 had no effect on the extracellular levels of GABA in the nucleus accumbens or thalamus. Additional studies showed that WAY-208466 (10 mg/kg, s.c.) preferentially elevated cortical GABA levels following both acute and chronic (14 day) administration, indicating that neurochemical tolerance does not develop following repeated 5-HT6 receptor stimulation. In hippocampal slice preparations (in vitro), 5-HT(6) receptor agonism attenuated stimulated glutamate levels elicited by sodium azide and high KCl treatment. Furthermore, in the rat schedule-induced polydipsia model of obsessive compulsive disorder (OCD), acute administration of WAY-181187 (56-178 mg/kg, po) decreased adjunctive drinking behavior in a dose-dependent manner. In summary, WAY-181187 and WAY-208466 are novel, selective, and potent 5-HT6 receptor agonists displaying a unique neurochemical signature in vivo. Moreover, these data highlight a previously undescribed role for 5-HT6 receptors to modulate basal GABA and stimulated glutamate transmission, as well as reveal a potential therapeutic role for this receptor in the treatment of some types of anxiety-related disorders (eg OCD).

Exposure to forced swim stress alters local circuit activity and plasticity in the dentate gyrus of the hippocampus

Studies have shown that, depending on its severity and context, stress can affect neural plasticity. Most related studies focused on synaptic plasticity and long-term potentiation (LTP) of principle cells. However, evidence suggests that following high-frequency stimulation, which induces LTP in principal cells, modifications also take place at the level of complex interactions with interneurons within the dentate gyrus, that is, at the local circuit level. So far, the possible effects of stress on local circuit activity and plasticity were not studied. Therefore, we set out to examine the possible alterations in local circuit activity and plasticity following exposure to stress. Local circuit activity and plasticity were measured by using frequency dependant inhibition (FDI) and commissural modulation protocols following exposure to a 15 minute-forced swim trial. Exposure to stress did not alter FDI. The application of theta-burst stimulation (TBS) reduced FDI in both control and stressed rats, but this type of plasticity was greater in stressed rats. Commissural-induced inhibition was significantly higher in stressed rats both before and after applying theta-burst stimulation. These findings indicate that the exposure to acute stress affects aspects of local circuit activity and plasticity in the dentate gyrus. It is possible that these alterations underlie some of the behavioral consequences of the stress experience.

Role of GABA in anxiety and depression

This review assesses the parallel data on the role of gamma-aminobutyric acid (GABA) in depression and anxiety. We review historical and new data from both animal and human experimentation which have helped define the key role for this transmitter in both these mental pathologies. By exploring the overlap in these conditions in terms of GABAergic neurochemistry, neurogenetics, brain circuitry, and pharmacology, we develop a theory that the two conditions are intrinsically interrelated. The role of GABAergic agents in demonstrating this interrelationship and in pointing the way to future research is discussed.

Pre-germinated brown rice could enhance maternal mental health and immunity during lactation

BACKGROUND

Rice is a dietary staple worldwide, especially pre-germinated brown rice has recently been widely served in Japan because of its abundant nutrition. Relationship between lactation and pre-germinated brown rice has attracted interest in terms of mental health and immunity.

AIM OF THE STUDY

To demonstrate that Japanese foods are beneficial for psychosomatic health, the effects of pre-germinated brown rice on the mental status and immunological features during lactation were investigated.

METHODS

Forty-one breast-feeding mothers were recruited, and randomly divided into two groups. One group took pre-germinated brown rice and the other white rice (control) as their staple diet for 2 weeks. The Profile of Mood States (POMS) and salivary amylase activity as psychological indices and secretory IgA (s-IgA) and lactoferrin (LTF) in breast milk as immunological indices were determined before and after dietary intervention, and changes were investigated.

RESULTS

In the psychological assessment, the scores of depression, anger-hostility, and fatigue were decreased on POMS analysis in the pre-germinated brown rice diet group, resulting in a significant decrease in total mood disturbance (TMD). The salivary amylase activity measurement suggested that resistance to stress was increased in the pre-germinated brown rice diet group. On the immunological assessment, the s-IgA level was significantly increased in the pre-germinated brown rice diet group.

CONCLUSION

We have shown that pre-germinated brown rice may have beneficial effects on psychosomatic health.