Presencia de autoanticuerpos anti islotes pancreáticos en diabetes tipo 1 durante la edad pediátrica / Presence of anti-pancreatic islet autoantibodies in type 1 diabetes in children

En la Diabetes tipo 1 (DM1) la pérdida de células ß pancreáticas es consecuencia de un proceso de autoinmunidad que cursa con la presencia de autoanticuerpos anti-islotes pancreáticos (AAPs). Estos AAPs son marcadores útiles para la clasificación de la enfermedad. En un centro pediátrico de tercer nivel se analizó la frecuencia de presentación de GADA, IA-2A, ZnT8A e IAA en un grupo con reciente debut entre enero 2018 y agosto 2021 (n= 90). Además, se investigó la frecuencia de presentación y relación de los AAPs con la edad, sexo y tiempo de evolución en pacientes en seguimiento (n= 240). En el grupo de debut se obtuvo positividad de GADA, IA-2A, ZnT8A y IAA en 77,8; 60; 62 y 47,8% de los pacientes respectivamente, un 4% no presentó AAPs. El 95,6% de los pacientes presentaron al menos un AAPs positivo. La frecuencia de IAA en el grupo en debut fue mayor en menores de 5 años. En el grupo en seguimiento el 75,2% resultaron GADA positivo (85,7% en mujeres y 62,8% en varones) p<0,05. IA-2A y ZnT8A fueron positivos en 45 y 51.7% respectivamente. El 91% presentaron al menos un AAP positivo. En este grupo se evidenció una menor positividad en función del tiempo de evolución. Se pudo determinar la frecuencia de presentación de los AAPs en un grupo en debut y la relación con la edad, sexo y tiempo de evolución en pacientes en seguimiento. La determinación de APPs facilita la correcta clasificación y elección de la terapia adecuada (AU)

In type 1 diabetes (DM1) the loss of pancreatic ß-cells is a consequence of an autoimmune process that results in the presence of pancreatic anti-islet autoantibodies (PAAs). PAAs are useful markers for the classification of the disease. The frequency of presentation of GADA, IA-2A, ZnT8A, and IAA in a group with recent debut seen between January 2018 and August 2021 (n= 90) was analyzed in a tertiary pediatric center. In addition, we investigated the frequency of presentation and association of PAAs with age, sex, and time of evolution in patients in follow-up (n= 240). In the debut group, GADA, IA2A, ZnT8A, and IAA positivity was found in 77.8, 60, 62, and 47.8% of patients, respectively; no PAAs were observed in 4% of the patients. Overall, 95.6% presented at least one positive PAA. The frequency of IAA in the debut group was higher in children younger than 5 years. In the follow-up group, 75.2% were GADA positive (85.7% of females and 62.8% of males) p<0.05. IA-2A and ZnT8A were positive in 45 and 51.7% respectively. Ninety-one percent presented with at least one positive PAA. In this group, a lower positivity was evidenced as a function of the time of evolution. The frequency of presentation of PAAs in a debut group and the relationship with age, sex, and time of evolution in patients in follow-up was demonstrated. The assessment of PAAs facilitates the correct classification and choice of adequate therapy (AU)

Efficient biosynthesis of γ-aminobutyric acid by rationally engineering the catalytic pH range of a glutamate decarboxylase from Lactobacillus plantarum / 生物工程学报

γ-aminobutyric acid can be produced by a one-step enzymatic reaction catalyzed by glutamic acid decarboxylase. The reaction system is simple and environmentally friendly. However, the majority of GAD enzymes catalyze the reaction under acidic pH at a relatively narrow range. Thus, inorganic salts are usually needed to maintain the optimal catalytic environment, which adds additional components to the reaction system. In addition, the pH of solution will gradually rise along with the production of γ-aminobutyric acid, which is not conducive for GAD to function continuously. In this study, we cloned the glutamate decarboxylase LpGAD from a Lactobacillus plantarum capable of efficiently producing γ-aminobutyric acid, and rationally engineered the catalytic pH range of LpGAD based on surface charge. A triple point mutant LpGADS24R/D88R/Y309K was obtained from different combinations of 9 point mutations. The enzyme activity at pH 6.0 was 1.68 times of that of the wild type, suggesting the catalytic pH range of the mutant was widened, and the possible mechanism underpinning this increase was discussed through kinetic simulation. Furthermore, we overexpressed the Lpgad and LpgadS24R/D88R/Y309K genes in Corynebacterium glutamicum E01 and optimized the transformation conditions. An optimized whole cell transformation process was conducted under 40 ℃, cell mass (OD600) 20, 100 g/L l-glutamic acid substrate and 100 μmol/L pyridoxal 5-phosphate. The γ-aminobutyric acid titer of the recombinant strain reached 402.8 g/L in a fed-batch reaction carried out in a 5 L fermenter without adjusting pH, which was 1.63 times higher than that of the control. This study expanded the catalytic pH range of and increased the enzyme activity of LpGAD. The improved production efficiency of γ-aminobutyric acid may facilitate its large-scale production.

Ten years follow up of first degree relatives of type 1 diabetes patients: presence of autoimmune biomarkers and the progression to diabetes in a retrospective cohort

ABSTRACT Objective: The aim of the study was to assess the autoimmunity in first degrees relatives (FDR) of patients with type 1 diabetes (T1DM) and the progression to T1DM after 10 years of follow up in the Brazilian population. Subjects and methods: Non-diabetic FDR of T1DM patients were interviewed and blood was drawn for autoantibodies measurement (GADA, IA-2A, IAA, ZnT8A). Serum samples were analyzed by standard radioligand binding assays performed at the Federal University of Rio de Janeiro (GADA, IAA and IA2A), and at the Skäne University Hospital, Sweden (ZnT8A). The FDR were interviewed by phone after 10 years to determine if they had developed T1DM. Descriptive statistical analysis was performed and results were described as means and standard deviation (SD). Results: 81 individuals were analyzed. Thirteen subjects had positive autoantibodies associated with T1DM.10 were positive for 1 autoantibody and 3 subjects were positive for multiple autoantibodies (1 of them showed positivity for 2 autoantibodies - GADA, ZnT8A - and the other two were positive for 3 autoantibodies - GADA, IA2A, ZnT8A). The 3 subjects with multiple positive autoantibodies developed T1DM within 10 years. Conclusions: In Brazilian FDR of T1DM patients, the positivity for multiple autoantibodies indicate a greater chance of progression to T1DM, similar to observed in Caucasians. ZnT8A was helpful in the risk assessment for T1DM development.

Low rate of latent autoimmune diabetes in adults (LADA) in patients followed for type 2 diabetes: A single centers experience in Turkey

ABSTRACT Objective In this study, we aimed to determine the frequency of and the clinical and metabolic features of patients with latent autoimmune diabetes in adults (LADA) at a single center in Turkey. Subjects and methods Patients over 30 years of age diagnosed with type 2 diabetes who did not require insulin for a minimum of 6 months following diagnosis were included. Data from 324 patients (163 women; 161 men), with a mean age of 54.97 ± 7.53 years, were analyzed in the study. Levels of antibodies to glutamate decarboxylase (anti-GAD) were measured in all patients, and LADA was diagnosed in patients testing positive for anti-GAD antibodies. Results Anti-GAD positivity was identified in 5 patients (1.5%). Family history of diabetes, body mass index (BMI), age, sex distribution, insulin resistance, serum triglycerides, high-density lipoprotein, and low-density lipoprotein were similar in the LADA and type 2 diabetes patients. Median HbA1c was significantly higher (10.8% vs. 7.38%, p = 0.002) and fasting C-peptide was lower (0.75 ng/mL vs. 2.82 ng/mL, p = 0.009) in patients with LADA compared to in those with type 2 diabetes. Among the 5 patients with LADA, 4 were positive for antithyroid peroxidase antibodies. The median disease duration was relatively shorter among patients with LADA (4 years vs. 7 years, p = 0.105). Conclusion We observed a LADA frequency of 1.5% among Turkish patients followed for type 2 diabetes. The presence of obesity and metabolic syndrome did not exclude LADA, and patients with LADA had worse glycemic control than patients with type 2 diabetes did.

Calpain-2 as a Treatment Target in Prenatal Stress-induced Epileptic Spasms in Infant Rats

Stress can induce a serious epileptic encephalopathy that occurs during early infancy. Recent studies have revealed that prenatal stress exposure is a risk factor for the development of infantile spasms. Our previous work demonstrates that prenatal stress with betamethasone-induced alterations to the expression of the K⁺/Cl⁻ co-transporter (KCC2) in gamma-aminobutyric acid (GABA) interneurons lowers the seizure threshold in exposed animals. Here, we further investigated the mechanisms involved in this KCC2 dysfunction and explored possible treatment options. We stressed Sprague-Dawley rats prenatally and further treated dams with betamethasone on gestational day 15, which increases seizure susceptibility and NMDA (N-Methyl-D-aspartate)-triggered spasms on postnatal day 15. In this animal model, first, we evaluated baseline calpain activity. Second, we examined the cleavage and dephosphorylation of KCC2. Finally, we checked the effect of a calpain inhibitor on seizure occurrence. The phosphorylated-N-methyl-D-aspartate Receptor 2B (NR2B):non-phosphorylated NR2B ratio was found to be higher in the cortex of the prenatally stressed beta-methasone model. We further found that the betamethasone model exhibited increased phosphorylation of calpain-2 and decreased phosphorylation of KCC2 and Glutamic acid decarboxylase 67 (GAD67). After using a calpain inhibitor in prenatal-stress rats, the seizure frequency decreased, while latency increased. GABAergic depolarization was further normalized in prenatal-stress rats treated with the calpain inhibitor. Our study suggests that calpain-dependent cleavage and dephosphorylation of KCC2 decreased the seizure threshold of rats under prenatal stress. Calpain-2 functions might, thus, be targeted in the future for the development of treatments for epileptic spasms.

Increasing the thermostability of glutamate decarboxylase from Lactobacillus brevis by introducing proline / 生物工程学报

Glutamate decarboxylase, a unique pyridoxal 5'-phosphate-dependent enzyme, catalyzes α-decarboxylation of L-glutamate to γ-aminobutyrate. However, glutamate decarboxylase from different sources has the common problem of poor thermostability that affects its application in industry. In this study, proline was introduced at 13 different positions in glutamate decarboxylase by using the design strategy of homologous sequence alignment between Thermococcus kodakarensis and Lactobacillus brevis CGMCC No.1306. A mutant enzyme G364P with higher thermostability was obtained. Compared to the wild type, thermostability of the mutant G364P was significantly improved, the half-life time (t1/2) at 55 °C and the semi-inactivation temperature (T₅₀ ¹⁵) of the mutant G364P increased 19.4 min and 5.3 °C, respectively, while kcat/Km of the mutant enzyme remained nearly unchanged. Further analysis of their thermostability by molecular dynamics simulations were performed. The root mean square deviation of G364P and root mean square fluctuation in the loop region including G364 were lower than the wild type at 313 K for 10 ns, and G364P increased one hydrophobic interaction in the loop region. It proves that mutation of flexible 364-Gly to rigid proline endows glutamate decarboxylase with enhanced thermostability.

Uso de plasmaféresis para el manejo del síndrome de la persona rígida / Use of plasmapheresis for the management of the syndrome of the rigid person

Introducción: el síndrome de la persona rígida (SPR) es una patología infrecuente caracterizada por la activación involuntaria de la unidad motora, causando rigidez fluctuante de la musculatura axial, espasmos musculares dolorosos y actividad motora continua en la electromiografía. En la mayoría de pacientes se encuentran niveles elevados de anticuerpos antiácido glutámico descarboxilasa. Presentación del caso: paciente de género femenino de 60 años de edad, con persistencia de sintomatología espasmódica muscular a pesar del manejo con medicamentos agonistas GABA e inmunomoduladores, por lo que se consideró el uso de plasmaféresis como tercera línea de tratamiento. Conclusiones: la experiencia con el uso de la técnica es favorable, hay disminución de los espasmos musculares en más del 50% al cabo de 7 sesiones. Aunque la plasmaféresis produjo alivio sintomático, son necesarios nuevos ensayos clínicos y reportes de caso para determinar su beneficio clínico y así protocolizar su aplicación.

Introduction: Stiff person syndrome (SPS) is an infrequent pathology, characterized by the involuntary activation of the motor unit, causing fluctuating rigidity of the axial muscles, painful muscle spasms and continuous motor activity in electromyography. In most patients, high levels of anti-glutamic acid decarboxylase antibodies are found. Case presentation: Female patient of 60 years of age, with persistence of muscular spasmodic symptoms despite management with GABA agonist drugs and immuno modulators, for which the use of plasmapheresis as the third line of treatment was considered. Conclusions: The experience in the use of the technique is favorable, with a decrease in muscle spasms greater than 50% after 7 sessions. Although plasmapheresis produced symptomatic relief, new clinical trials and case reports are necessary to determine its clinical benefit and thus protocolize its application

A Critical Time-Window for the Selective Induction of Hippocampal Memory Consolidation by a Brief Episode of Slow-Wave Sleep / 神经科学通报·英文版

Although extensively studied, the exact role of sleep in learning and memory is still not very clear. Sleep deprivation has been most frequently used to explore the effects of sleep on learning and memory, but the results from such studies are inevitably complicated by concurrent stress and distress. Furthermore, it is not clear whether there is a strict time-window between sleep and memory consolidation. In the present study we were able to induce time-locked slow-wave sleep (SWS) in mice by optogenetically stimulating GABAergic neurons in the parafacial zone (PZ), providing a direct approach to analyze the influences of SWS on learning and memory with precise time-windows. We found that SWS induced by light for 30 min immediately or 15 min after the training phase of the object-in-place task significantly prolonged the memory from 30 min to 6 h. However, induction of SWS 30 min after the training phase did not improve memory, suggesting a critical time-window between the induction of a brief episode of SWS and learning for memory consolidation. Application of a gentle touch to the mice during light stimulation to prevent SWS induction also failed to improve memory, indicating the specific role of SWS, but not the activation of PZ GABAergic neurons itself, in memory consolidation. Similar influences of light-induced SWS on memory consolidation also occurred for Y-maze spatial memory and contextual fear memory, but not for cued fear memory. SWS induction immediately before the test phase had no effect on memory performance, indicating that SWS does not affect memory retrieval. Thus, by induction of a brief-episode SWS we have revealed a critical time window for the consolidation of hippocampus-dependent memory.

Dendritic Cell Factor 1-Knockout Results in Visual Deficit Through the GABA System in Mouse Primary Visual Cortex / 神经科学通报·英文版

The visual system plays an important role in our daily life. In this study, we found that loss of dendritic cell factor 1 (DCF1) in the primary visual cortex (V1) caused a sight deficit in mice and induced an abnormal increase in glutamic acid decarboxylase 67, an enzyme that catalyzes the decarboxylation of glutamate to gamma aminobutyric acid and CO, particularly in layer 5. In vivo electrophysiological recordings confirmed a decrease in delta, theta, and beta oscillation power in DCF1-knockout mice. This study presents a previously unknown function of DCF1 in V1, suggests an unknown contact between DCF1 and GABA systems, and provides insight into the mechanism and treatment of visual deficits.

Prevalence of autoimmune thyroiditis in patients with type 1 diabetes: a long-term follow-up study

PURPOSE: Type 1 diabetes mellitus (DM) is associated with autoimmune diseases such as thyroiditis. Therefore, we aimed to investigate the prevalence of autoimmune thyroiditis in patients with type 1 DM. METHODS: A total of 102 patients who were diagnosed and followed up (mean age, 8.1±4.0 years) in Ajou University Hospital were enrolled in this study. All the patients were evaluated for beta cell autoimmunity, including insulin autoantibody, glutamic acid decarboxylase antibodies (GADA), and islet cell antibody. Moreover, autoantibodies to thyroid peroxidase and thyroglobulin were assessed at initial diagnosis and annually thereafter. RESULTS: The mean patient age (49 men and 53 women) was 19.2±4.8 years. The prevalence of at least one thyroid antibody was 30.4%. Patients with thyroid anti­bodies had a significantly higher frequency of GADA at the time of the diagnosis. Autoimmune thyroiditis was more prevalent in the older age group. GADA was a significant risk factor for development of thyroid autoantibodies after diagnosis of type 1 DM (odds ratio, 4.45; 95% confidence interval, 1.399–14.153). CONCLUSIONS: In patients with type 1 DM, the prevalence of autoimmune thyroiditis was higher than in the general population. Moreover, GADA positivity at diagnosis was associated with thyroid autoimmunity.

Concurrence of Diabetic Ketoacidosis and Acute Ischemic Stroke due to Moyamoya Disease / 대한소아신경학회지

Although the etiology of moyamoya disease (MMD) remains unknown, autoimmunity is one of the proposed pathogeneses. Unlike other autoimmune disorders that are associated with cerebral arteritis, concurrence of MMD and diabetes mellitus (DM) is rare. However, we encountered a patient with concurrent diabetic ketoacidosis (DKA) and acute ischemic stroke due to MMD. Our patient was diagnosed with glutamic acid decarboxylase antibody-positive type 2 DM (T2DM) based on laboratory and physical examination findings. Brain magnetic resonance images revealed an acute ischemic stroke in the left cerebral hemisphere and bilateral diffuse stenosis/occlusion in the middle cerebral artery and multiple collaterals. Thus, here, we report a patient with both T2DM and MMD who developed an acute ischemic stroke that was complicated by DKA.

Long-term prenatal stress increases susceptibility of N-methyl-D-aspartic acid-induced spasms in infant rats / 소아과

PURPOSE: Infantile spasms, also known as West syndrome, is an age-specific epileptic seizure. Most patients with this condition also exhibit delayed development. This study aimed to determine the effect of long-term prenatal stress on susceptibility to infantile spasms. METHODS: We subjected pregnant rats to acute or chronic immobilization stress. Resulting offspring received N-methyl-D-aspartic acid (15 mg/kg, intraperitoneally) on postnatal day 15, and their behaviors were observed 75 minutes after injection. The expression of KCC2 and GAD67 was also determined using immunohistochemistry. RESULTS: Exposure to long-term prenatal stress increased the frequency of spasms and decreased the latency to onset of spasms compared with offspring exposed to short-term prenatal stress. Expression of KCC2 and GAD67 also decreased in the group exposed to long-term prenatal stress compared with the group exposed to short-term prenatal stress. CONCLUSION: Our study suggests that exposure to long-term prenatal stress results in increased susceptibility to seizures.

Prevalence of pancreatic autoantibodies in non-diabetic patients with autoimmune thyroid disease and its relation to insulin secretion and glucose tolerance

ABSTRACT Objective We evaluated the prevalence of glutamic acid decarboxylase (GADA) and tyrosine phosphatase-protein antibodies (IA2A), their titers and their relation to first phase insulin response (FPIR) and glucose tolerance in autoimmune thyroid diseases (ATDs) patients. Subjects and methods Graves' disease (GD; n = 181) and Hashimoto's thyroiditis (HT; n = 143) patients in addition to healthy controls (n = 93) were studied. Secondly, FPIR and oral glucose tolerance tests (OGTT) were performed in 11 anti-pancreatic islet-cell (+) and in 20 anti-pancreatic-cell (-) patients. Results There was a non significant trend for higher prevalence of GADA positivity in GD vs HT (7.2% vs 2% p = 0.06), but the GADA titers were higher in HT. We also did not find a significant difference in IA2 prevalence (0.7% vs 0.0%) between these two groups or compared to the control group. In the subsequent analysis, low FPIR was found in 10% of these patients but without statistical difference for OGTT between pancreatic antibody-positive and -negative patients. Conclusion A trend for greater prevalence of GADA was observed for GD patients than for HT or control. However, the titers of these autoantibodies were higher in HT patients, but there was no significant relation to insulin secretion and glucose tolerance at that moment and stage of autoimmune diseases.

Molecular cloning, expression, and immobilization of glutamate decarboxylase from Lactobacillus fermentum YS2

Background: GABA (γ-aminobutyric acid) is a four-carbon nonprotein amino acid that has hypotensive, diuretic, and tranquilizing properties. Glutamate decarboxylase (GAD) is the key enzyme to generate GABA. A simple and economical method of preparing and immobilizing GAD would be helpful for GABA production. In this study, the GAD from Lactobacillus fermentum YS2 was expressed under the control of a stress-inducible promoter and was purified and immobilized in a fusion form, and its reusability was investigated. Results: The fusion protein CBM-GAD was expressed in Escherichia coli DH5α carrying pCROCB-gadB, which contained promoter PrpoS, cbm3 (family 3 carbohydrate-binding module from Clostridium thermocellum) coding sequence, the gadB gene from L. fermentum YS2 coding for GAD, and the T7 terminator. After a one-step purification of CBM-GAD using regenerated amorphous cellulose (RAC) as an adsorbent, SDS-PAGE analysis revealed a clear band of 71 kDa; the specific activity of the purified fusion protein CBM-GAD reached 83.6 ± 0.7 U·mg-1. After adsorption onto RAC, the immobilized GAD with CBM3 tag was repeatedly used for GABA synthesis. The protein-binding capacity of RAC was 174 ± 8 mg·g-1. The immobilized CBM-GAD could repeatedly catalyze GABA synthesis, and 8% of the initial activities was retained after 10 uses. We tested the conversion of monosodium glutamate to GABA by the immobilized enzyme; the yield reached 5.15 g/L and the productivity reached 3.09 g/L·h. Conclusions: RAC could be used as an adsorbent in one-step purification and immobilization of CBM-GAD, and the immobilized enzyme could be repeatedly used to catalyze the conversion of glutamate to GABA.

Clinical characteristics of patients with cerebellar ataxia associated with anti-GAD antibodies / Características clínicas de pacientes com ataxia cerebelar associada a anticorpos anti-GAD

ABSTRACT The enzyme glutamic acid decarboxylase (GAD), present in GABAergic neurons and in pancreatic beta cells, catalyzes the conversion of gamma-aminobutyric acid (GABA). The cerebellum is highly susceptible to immune-mediated mechanisms, with the potentially treatable autoimmune cerebellar ataxia associated with the GAD antibody (CA-GAD-ab) being a rare, albeit increasingly detected condition. Few cases of CA-GAD-ab have been described. Methods This retrospective and descriptive study evaluated the clinical characteristics and outcomes of patients with CA-GAD-ab. Result Three patients with cerebellar ataxia, high GAD-ab titers and autoimmune endocrine disease were identified. Patients 1 and 2 had classic stiff person syndrome and insidious-onset cerebellar ataxia, while Patient 3 had pure cerebellar ataxia with subacute onset. Patients received intravenous immunoglobulin therapy with no response in Patients 1 and 3 and partial recovery in Patient 2. Conclusion CA-GAD-ab is rare and its clinical presentation may hamper diagnosis. Clinicians should be able to recognize this potentially treatable autoimmune cerebellar ataxia.

RESUMO A enzima ácido glutâmico descarboxilase (GAD), presente nos neurônios GABAérgicos e células beta do pâncreas, catalisa a conversão do ácido gama-aminobutírico (GABA). O cerebelo é altamente susceptível a mecanismos imunomediados, sendo a ataxia cerebelar associada ao anticorpo anti-GAD (CA-GAD) uma doença potencialmente tratável. Embora rara, sua frequência é crescente, com poucos casos descritos. Métodos Estudo retrospectivo e descritivo avaliando características clínicas e desfechos da CA-GAD. Resultados Três pacientes com CA-GAD, altos títulos de anti-GAD e doença endócrina autoimune foram identificados. Os pacientes 1 e 2 tinham síndrome da pessoa rígida em forma clássica e apresentação insidiosa da ataxia cerebelar, enquanto o paciente 3 tinha ataxia cerebelar pura e apresentação subaguda. Os pacientes 1 e 3 não melhoraram com imunoglobulina intravenosa e o paciente 2 teve recuperação parcial. Conclusão A CA-GAD é rara e pode ter apresentação clínica desafiadora. Os médicos devem ser capazes de reconhecer essa forma potencialmente tratável de ataxia cerebelar autoimune.

Rosmarinic Acid Potentiates Pentobarbital-Induced Sleep Behaviors and Non-Rapid Eye Movement (NREM) Sleep through the Activation of GABA(A)-ergic Systems

It has been known that RA, one of major constituents of Perilla frutescens which has been used as a traditional folk remedy for sedation in oriental countries, shows the anxiolytic-like and sedative effects. This study was performed to know whether RA may enhance pentobarbital-induced sleep through γ-aminobutyric acid (GABA)(A)-ergic systems in rodents. RA (0.5, 1.0 and 2.0 mg/kg, p.o.) reduced the locomotor activity in mice. RA decreased sleep latency and increased the total sleep time in pentobarbital (42 mg/kg, i.p.)-induced sleeping mice. RA also increased sleeping time and number of falling sleep mice after treatment with sub-hypnotic pentobarbital (28 mg/kg, i.p.). In electroencephalogram (EEG) recording, RA (2.0 mg/kg) not only decreased the counts of sleep/wake cycles and REM sleep, but also increased the total and NREM sleep in rats. The power density of NREM sleep showed the increase in δ-waves and the decrease in α-waves. On the other hand, RA (0.1, 1.0 and 10 μg/ml) increased intracellular Cl− influx in the primary cultured hypothalamic cells of rats. RA (p.o.) increased the protein expression of glutamic acid decarboxylase (GAD(65/67) ) and GABA(A) receptors subunits except β1 subunit. In conclusion, RA augmented pentobarbital-induced sleeping behaviors through GABA(A)-ergic transmission. Thus, it is suggested that RA may be useful for the treatment of insomnia.

In Silico Model-driven Assessment of the Effects of Brain-derived Neurotrophic Factor Deficiency on Glutamate and Gamma-Aminobutyric Acid: Implications for Understanding Schizophrenia Pathophysiology

OBJECTIVE: Deficient brain-derived neurotrophic factor (BDNF) is one of the important mechanisms underlying the neuroplasticity abnormalities in schizophrenia. Aberration in BDNF signaling pathways directly or circuitously influences neurotransmitters like glutamate and gamma-aminobutyric acid (GABA). For the first time, this study attempts to construct and simulate the BDNF-neurotransmitter network in order to assess the effects of BDNF deficiency on glutamate and GABA. METHODS: Using CellDesigner, we modeled BDNF interactions with calcium influx via N-methyl-D-aspartate receptor (NMDAR)-Calmodulin activation; synthesis of GABA via cell cycle regulators protein kinase B, glycogen synthase kinase and β-catenin; transportation of glutamate and GABA. Steady state stability, perturbation time-course simulation and sensitivity analysis were performed in COPASI after assigning the kinetic functions, optimizing the unknown parameters using random search and genetic algorithm. RESULTS: Study observations suggest that increased glutamate in hippocampus, similar to that seen in schizophrenia, could potentially be contributed by indirect pathway originated from BDNF. Deficient BDNF could suppress Glutamate decarboxylase 67-mediated GABA synthesis. Further, deficient BDNF corresponded to impaired transport via vesicular glutamate transporter, thereby further increasing the intracellular glutamate in GABAergic and glutamatergic cells. BDNF also altered calcium dependent neuroplasticity via NMDAR modulation. Sensitivity analysis showed that Calmodulin, cAMP response element-binding protein (CREB) and CREB regulated transcription coactivator-1 played significant role in this network. CONCLUSION: The study presents in silico quantitative model of biochemical network constituting the key signaling molecules implicated in schizophrenia pathogenesis. It provides mechanistic insights into putative contribution of deficient BNDF towards alterations in neurotransmitters and neuroplasticity that are consistent with current understanding of the disorder.

Ethanol Extract of Perillae Herba Enhances Pentobarbital-Induced Sleep and Non-Rapid Eye Movement (NREM) Sleep through GABA(A)-ergic Systems

Perillae Herba has been traditionally used for the sedation in the oriental countries. Therefore, this study was conducted to determine whether Perillae Herba ethanol extract (PHEE) enhances pentobarbital-induced sleeping behaviors in animals. In addition, the possible mechanisms are demonstrated. PHEE (12.5, 25 and 50 mg/kg. p.o.) reduced the locomotor activity in mice. PHEE reduced sleep latency and augmented the total sleep time in pentobarbital (42 mg/kg, i.p.)-induced sleep in mice. Furthermore, the number of sleeping mice treated with sub-hypnotic pentobarbital (28 mg/kg, i.p.) increased. PHEE (50 mg/kg. p.o.) decreased the sleep/wake cycles and wakefulness, and increased total sleeping time and NREM sleep in electroencephalogram (EEG) of rats. In addition, PHEE (0.1, 1.0 and 10 µg/ml) increased the intracellular Cl⁻ level through the GABA receptors in the hypothalamus of rats. Moreover, the protein of glutamate decarboxylase (GAD) was overexpressed by PFEE. It was found that PHEE enhanced pentobarbital-induced sleeping behaviors through GABA(A)-ergic transmissions.

Reexamination of Dopaminergic Amacrine Cells in the Rabbit Retina: Confocal Analysis with Double- and Triple-labeling Immunohistochemistry

Dopaminergic amacrine cells (DACs) are among the most well-characterized neurons in the mammalian retina, and their connections to AII amacrine cells have been described in detail. However, the stratification of DAC dendrites differs based on their location in the inner plexiform layer (IPL), raising the question of whether all AII lobules are modulated by dopamine release from DACs. The present study aimed to clarify the relationship between DACs and AII amacrine cells, and to further elucidate the role of dopamine at synapses with AII amacrine cell. In the rabbit retina, DAC dendrites were observed in strata 1, 3, and 5 of the IPL. In stratum 1, most DAC dendritic varicosities—the presumed sites of neurotransmitter release—made contact with the somata and lobular appendages of AII amacrine cells. However, most lobular appendages of AII amacrine cells localized within stratum 2 of the IPL exhibited little contact with DAC varicosities. In addition, double- or triple-labeling experiments revealed that DACs did not express the GABAergic neuronal markers anti-GABA, vesicular GABA transporter, or glutamic acid decarboxylase. These findings suggest that the lobular appendages of AII amacrine cells are involved in at least two different circuits. We speculate that the circuit associated with stratum 1 of the IPL is modulated by DACs, while that associated with stratum 2 is modulated by unknown amacrine cells expressing a different neuroactive substance. Our findings further indicate that DACs in the rabbit retina do not use GABA as a neurotransmitter, in contrast to those in other mammals.