The involvement of sodium and calcium ions in the release of amino acid neurotransmitters from mouse cortical slices elicited by hyperforin

Hyperforin is currently considered to be the major active antidepressant constituent of the medicinal herb St. John's wort (Hypericum perforatum L.). The mechanism of action however, is still largely unknown, although the involvement of sodium and calcium has been recently inferred. In the present study hyperforin (5 microM) significantly potentiated the release of endogenous aspartate and glutamate from mouse cortical slices when stimulated by veratridine or potassium. Hyperforin (5 microM) also stimulated the release of aspartate, glutamate, serine, glycine and GABA when perfused on its own. Perfusion of the sodium channel blocker, tetrodotoxin (TTX) inhibited the effect of hyperforin, whereas removal of extracellular calcium potentiated the effect. Our observations suggests that hyperforin increases the overflow of neurotransmitters from mouse cerebral cortex possibly through facilitating the entry of sodium into the neurone which leads to the release of calcium from intracellular stores.     

Effects of Glycine on the Catecholamine Levels and Activities of Alcohol-Metabolizing Enzymes in Rats with Alcohol Intoxication and Addiction

We studied in rats the effects of peroral glycine introduction on the contents of catecholamines (CA) – noradrenaline (NA) and dopamine (DA) – in different brain structures (hypothalamus, midbrain, and neocortex), as well as the levels of adrenaline (A), NA, and DA in the blood and the activity of alcohol-metabolizing (AlM) enzymes – alcohol dehydrogenase (AlDH) and aldehyde dehydrogenase (AdhDH) – in the blood serum. The experimental group included animals with a disposition to alcohol consumption under conditions of free choice for drinking between an alcohol solution and water. The measurements were performed in animals in the state of acute alcohol intoxication (i.p. injection of 4 g/kg ethanol) or chronic alcohol addiction (formed due to a 3-month-long free access to ethanol solution). Introduction of 150 mg/kg glycine increased the NA and DA contents (the latter, to a lesser extent) in all examined brain structures; the NA level in the blood increased, while that of DA decreased. Under conditions of acute alcohol intoxication and chronic alcohol addiction, the ratio of the activities of AlM enzymes, AdhDH/AlDH, was significantly shifted toward values indicative of accumulation of acetaldehyde (AcAdh) in the tissues. This was accompanied by noticeable modifications of the CA contents in the brain structures and blood of the rats; in particular, the [DA]/[NA] ratio in the brain significantly increased. Introduction of glycine under conditions of acute alcohol intoxication provided normalization of the AdhDH/AlDH activity ratio. Obvious trends toward normalization of the CA levels in the brain structures were also observed in both acute and chronic experiments. In the latter case, the glycine treatment course resulted in a drop in the daily alcohol consumption by the animals. We conclude that glycine, which binds AcAdh and modifies the metabolism of CA transmitters, exerts a significant corrective influence on the pathogenetic mechanisms of alcohol addiction. Our experimental findings demonstrate that there are contact points between the acetaldehyde and catecholamine hypotheses of pathogenesis of alcoholism.     

Role of adiponectin and inflammation in insulin resistance of Mc3r and Mc4r knockout mice

Objective: To investigate the involvement of hypoadiponectinemia and inflammation in coupling obesity to insulin resistance in melanocortin‐3 receptor and melanocortin‐4 receptor knockout (KO) mice (Mc3/4rKO). Research Methods and Procedures: Sera and tissue were collected from 6‐month‐old Mc3rKO, Mc4rKO, and wild‐type C57BL6J litter mates maintained on low‐fat diet or exposed to high‐fat diet (HFD) for 1 or 3 months. Inflammation was assessed by both real‐time polymerase chain reaction analysis of macrophage‐specific gene expression and immunohistochemistry. Results: Mc4rKO exhibited hypoadiponectinemia, exacerbated by HFD and obesity, previously reported in murine models of obesity. Mc4r deficiency was also associated with high levels of macrophage infiltration of adipose tissue, again exacerbated by HFD. In contrast, Mc3rKO exhibited normal serum adiponectin levels, irrespective of diet or obesity, and a delayed inflammatory response to HFD relative to Mc4rKO. Discussion: Our findings suggest that severe insulin resistance of Mc4rKO fed a HFD, as reported in other models of obesity such as leptin‐deficient (Lep^ob/Lep^ob) and KK‐A^y mice, is linked to reduced serum adiponectin and high levels of inflammation in adipose tissue. Conversely, maintenance of normal serum adiponectin may be a factor in the relatively mild insulin‐resistant phenotype of severely obese Mc3rKO. Mc3rKO are, thus, a unique mouse model where obesity is not associated with reduced serum adiponectin levels. A delay in macrophage infiltration of adipose tissue of Mc3rKO during exposure to HFD may also be a factor contributing to the mild insulin resistance in this model.     

Biological effects of prolonged exposure to ELF electromagnetic fields in rats: III. 50 Hz electromagnetic fields

Groups of adult male Sprague Dawley rats (64 rats each) were exposed for 8 months to electromagnetic fields (EMF) of two different field strength combinations: 5μT - 1kV/m and 100μT - 5kV/m. A third group was sham exposed. Field exposure was 8 hrs/day for 5 days/week. Blood samples were collected for hematology determinations before the onset of exposure and at 12 week intervals. At sacrifice, liver, heart, mesenteric lymph nodes, bone marrow, and testes were collected for morphology and histology assessments, while the pineal gland and brain were collected for biochemical determinations. At both field strength combinations, no pathological changes were observed in animal growth rate, in morphology and histology of the collected tissue specimens (liver, heart, mesenteric lymph nodes, testes, bone marrow), and in serum chemistry. An increase in norepinephrine levels occurred in the pineal gland of rats exposed to the higher field strength. The major changes in the brain involved the opioid system in frontal cortex, parietal cortex, and hippocampus. From the present findings it may be hypothesized that EMF may cause alteration of some brain functions. Bioelectromagnetics 19:57–66, 1998. © 1998 Wiley-Liss, Inc.     

Synthesis and histamine H3 receptor activity of 4-(n-alkyl)-1H-imidazoles and 4-(ω-phenylalkyl)-1H-imidazoles

The influence of lipophilic moieties attached to a 4-1H-imidazole ring on the histamine H₃ receptor activity was systematically investigated. Series of 4-(n-alkyl)-1H-imidazoles and 4-(ω-phenylalkyl)-1H-imidazoles were prepared, with an alkyl chain varying from 2–9 methylene groups and from 1–9 methylene groups, respectively. The compounds were tested for their activity on the H₃ receptor under in vitro conditions. For the 4-(n-alkyl)-1H-imidazoles the activity is proportional to chain length, ranging from a pA₂ value of 6.3±0.2 for 4-(n-propyl)-1H-imidazole to a pA₂ value of 7.2±0.1 for 4-(n-decyl)-1H-imidazole. For the series 4-(ω-phenylalkyl)-4H-imidazoles an optimum in H₃ activity was found for the pentylene spacer: 4-(ω-phenylpentyl)-1H-imidazole has a pA₂ value of 7.8±0.1.     

柴桂温胆定志汤联合舍曲林对抑郁症患者血清单胺类神经递质和外周血单个核细胞PI3K/Akt信号通路的影响

摘要 目的：观察柴桂温胆定志汤联合舍曲林对抑郁症患者血清单胺类神经递质和外周血单个核细胞磷脂酰肌醇3激酶（PI3K）/蛋白激酶 B（Akt）信号通路的影响。方法：选择2018年10月~2020年6月期间北京市昌平区中西医结合医院收治的抑郁症患者128例,将患者根据信封抽签法分为对照组和实验组,各为64例。对照组患者接受舍曲林治疗,实验组患者接受柴桂温胆定志汤联合舍曲林治疗,观察治疗4周后两组疗效、各量表评分、血清单胺类神经递质和外周血单个核细胞PI3K/Akt信号通路情况,记录两组用药期间不良反应发生情况。结果：实验组的临床总有效率较对照组高（P<0.05）。治疗后,两组生活质量综合评定问卷（GQOLI-74）评分较治疗前升高,且实验组高于对照组（P<0.05）。治疗后,两组匹兹堡睡眠质量指数（PSQI）、汉密尔顿抑郁量表（HAMD）评分较治疗前降低,且实验组低于对照组（P<0.05）。治疗后,两组血清去甲肾上腺素（NE）、5-羟色胺（5-HT）、多巴胺（DA）水平较治疗前升高,且实验组高于对照组（P<0.05）。治疗后,两组PI3K蛋白、Akt蛋白、白介素-1β（IL-1β）、肿瘤坏死因子-α（TNF-α）水平较治疗前降低,且实验组低于对照组（P<0.05）。两组不良反应发生率对比无统计学差异（P>0.05）。结论：柴桂温胆定志汤联合舍曲林治疗抑郁症疗效显著,可改善患者睡眠情况,提高生活质量,调节血清单胺类神经递质水平,作用机制可能与调节PI3K/Akt信号通路有关。     

Evaluating the potential of thermal read‐out techniques combined with molecularly imprinted polymers for the sensing of low‐weight organic molecules

In recent years, there has been a tremendous increase in the papers published on synthetic recognition elements. Molecularly imprinted polymers (MIPs), also referred to as “man‐made mimics” of antibodies, are able to rebind their template molecules with high affinity. Advantages compared with those of natural receptors include their excellent thermal and chemical stability, low cost, and ease of the production process. However, their use in commercial biosensors is limited owing to the difficulty to incorporate MIPs into suitable sensing platforms and traditional detection techniques, such as chromatography, that require bulky and sophisticated equipment. In this review, we evaluate the potential to use MIPs combined with thermal read‐out for the detection of low‐weight organic molecules. We discuss thermal methods to study MIP‐template complexation and to determine neurotransmitters concentrations. In particular, we highlight the heat‐transfer method, a recent technique that is straightforward and low cost and requires minimal instrumentation. Until now, sample preparation involves a 2‐step process, making it time‐consuming, and measuring biological samples is difficult owing to the noise in the signal. Different sample preparation methods are discussed, and it will be demonstrated how this affects the thermal response. An outlook is given in novel methods that can simplify and speed up sample preparation. Finally, we show a novel thermal technique, which is based on the analysis of transport of thermal waves rather than evaluating the fixed heat‐transfer resistance. Through applying the concept of thermal waves, signal‐noise ratio is significantly increased, which results in lower detection limits and has potential for the study of biological samples.     

A functional circuit formed by the autonomic nerves and myofibroblasts controls mammalian alveolar formation for gas exchange

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The effects of doxycycline administration on amino acid neurotransmitters in an animal model of neonatal hypoxia-ischemia

Neonatal hypoxia-ischemia (HI) is a major contributor to many neurological, psychiatric and behavioral disorders. Previous studies in our laboratory have shown that a one-time dose of doxycycline (DOXY), even when given 3 h after HI insult, was neuroprotective and significantly reduced microglial activation and cleaved caspase-3 protein expression in the immature brain. In light of these data, the goal of this study was to investigate the effects of DOXY administration on amino acid neurotransmitters. Post-natal-day 7 rats received DOXY (10 mg/kg) or vehicle (VEH) concomitant with the onset of HI, and were euthanized 30 min, 1, 2 or 4 h post-HI (n ≥ 6). Extracted brains were either immediately dissected for frontal cortex, striatum and hippocampal regions, or removed in their entirety and flash frozen in isopentane for histological analyses. Dissected regions were homogenized and aliquots were prepared for high performance liquid chromatography (HPLC) analyses of amino acid levels and brain levels of DOXY. HPLC extraction revealed that systemic administration of DOXY resulted in mean drug levels of 867.1 ± 376.1 ng/g of brain tissue. Histological analyses revealed microglial activation, caspase-3 activation and neuronal degeneration consistent with a mild injury in the regions most vulnerable to HI. We found that HI caused significant, time-dependent, regional changes in brain amino acids including glutamate, GABA, alanine, aspartate, asparagine, serine, glutamine, glycine and taurine. HI significantly increased glutamate levels in the hippocampus (HI + VEH = 15.8 ± 3.1 ng/μg versus control = 11.8 ± 1.4 ng/μg protein) 4 h post-HI (p < 0.05). Pups treated with DOXY had lower glutamate levels (13.1 ± 2.4 ng/μg) when compared to VEH-treated pups (15.8 ± 3.1 ng/μg), however these values failed to reach significance. In addition, DOXY-treated pups had significantly lower alanine (HI + VEH = 1.1 ± 0.2 ng/μg versus HI + DOXY = 0.5 + 0.1 ng/μg) and serine (HI + VEH = 1.4 ± 0.4 ng/μg versus HI + DOXY = 0.7 + 0.1 ng/μg) levels in the hippocampus, 4 h post-HI. Similar normalizations and significant reductions in alanine and serine were seen in the cortex and striatum. These results show that in addition to its previously reported and well-documented anti-inflammatory and anti-apoptotic properties, DOXY has significant effects on amino acid neurotransmitters.     

A possible involvement of beta-endorphin, substance P, and serotonin in rat analgesia induced by extremely low frequency magnetic field

Most of the research concerning magnetic antinociception was focused on brief exposure less than 1 h. The main purpose of the present study was to determine the effect of extremely low frequency (ELF) magnetic field (MF) repeated exposures on rats in inducing antinociception and to find the effective analgesic "time window." Meanwhile this investigation was to examine the role of central beta-endorphin, substance P, and 5-HT in magnetic analgesia. We found tail flick latencies (TFLs) increased significantly after the rats were exposed to 55.6 Hz, 8.1 mT magnetic field for 4 days, 6 h each day. The analgesic effects seemed to decrease gradually when the rats were exposed daily for another 10 days. Their levels of TFLs decreased within 1 day when the rats were removed after a 4-day exposure. The concentrations of hypothalamus beta-endorphin, substance P, and brainstem serotonin (5-HT) were increased significantly on Day 4. However, no differences were found when rats were exposed for another 10 days, and there were no significant increases when rats were removed after the fourth day of exposure and tested for nociception on Days 5 and 7 with no changes in the biochemical markers at 7 days. These results suggest that the ELF magnetic field has analgesic effect, but only on Days 3 and 4. The effect may be associated with increases in endogenous beta-endorphin, substance P, and 5-HT stimulated by the 55.6 Hz, 8.1 mT magnetic field.