束缚加悬吊应激大鼠脑组织单胺类神经递质的变化及异丙酚对其的影响

目的研究麻醉剂异丙酚对束缚加悬吊应激大鼠脑组织不同脑区单胺类神经递质去甲肾上腺素(NE)、多巴胺(DA)、5-羟色胺(5-HT)含量的影响。方法 30只雄性SD大鼠随机分成3组,束缚加悬吊应激对照组(S组),小剂量异丙酚(5 mg/kg)组(p1组),大剂量异丙酚(10 mg/kg)组(p2组),输液后6 h,断头处死所有大鼠,取脑组织,荧光法测定不同脑区单胺类神经递质NE、DA、5-HT含量。结果小剂量异丙酚组脑干、小脑组织中5-HT明显降低,小脑组织中的NE明显升高;大剂量异丙酚组脑干、小脑组织中DA明显升高,小脑组织中的NE明显升高。结论异丙酚对应激大鼠脑组织不同脑区单胺类神经递质含量有不同的影响,5-HT的降低,NE、DA的升高可能与高血压有关。

孔雀草水煎液对小鼠抗抑郁作用及机制研究

目的:研究孔雀草水煎液对慢性温和刺激抑郁模型小鼠的抗抑郁作用。方法:雄性ICR小鼠随机分成5组,空白组、模型组、氟西汀组(3 mg/kg)、孔雀草组[0.5倍(1.125 g/kg)、2倍(4.5 g/kg)]。通过30 d不可预见性应激方法造抑郁小鼠模型,在15 d时,造模同时灌胃孔雀草水煎液,并检测其体质量变化。用糖水偏爱测试、强迫游泳实验和悬尾行为学测试来检测小鼠行为变化。在造模结束后断头取脑,用ELISA法检测脑内单胺类神经递质的含量。结果:模型组体质量明显低于空白组(P<0.05),且各用药组体质量与空白组之间无明显差别。模型组糖水偏爱度明显高于空白对照组(P<0.05);与模型组相比,氟西汀组和孔雀草各剂量组明显降低。在强迫游泳实验和悬尾实验中,模型组与空白组相比不动时间明显增加(P<0.05),氟西汀和各用药组能明显减少抑郁小鼠不动时间。模型脑内单胺类神经递质明显低于空白组(P<0.05),各给药组脑内单胺类神经递质含量增加。结论:孔雀草水煎液可以明显改善小鼠抑郁样行为,这与增加抑郁小鼠脑内单胺类神经递质含量有关,这可能是孔雀草抗抑郁作用的重要机制之一。

A high-performance liquid chromatography with fluorescence detection method for the simultaneous quantitation of monoamine neurotransmitters and their metabolites in subregions of rat brain

Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid） in different brain subregions of rats using a newly developed simple, sensitive and selective high-performance liquid chromatography with fluorescence detection （HPLC-FLD） method. In this new HPLC-FLD method, analytes were directly extracted and separated without deriveatization step within 20 min. The FLD wavelength was set at 280 nm and 330 nm for excitation and emission, respectively. The analytes were separated on an Agilent Eclipse Plus Cls column （4.6 mm×150 mm, 5.0 μm） equipped with an Agilent XDB-C18 security guard column （4.6 mm×12.5 mm, 5.0 lam）, and the column temperature was maintained at 35 ℃. The mobile phase for elution was isocratic. The mobile phase consisted of citric acid buffer （50 mmol/L citric acid, 50 mmol/L sodium acetate, 0.5 mmol/L octane sulfonic acid sodium salt, 0.5 mmol/L Na2EDTA and 5 mmol/L triethylamine, pH 3.8） and methanol （90：10, v/v） at a flow rate of 1.0 mL/min. The detection limit （DL） was 0.9-23 nM for all the MANTs and their metabolites with a sample volume of 50 μL. The method was shown to be highly reproducible in terms of peak area （intraday, 0.08%-1.85% RSD, n = 5）. The simultaneous measurement of these MANTs and their metabolites improved our understanding of the neurochemistry in the central nervous system （CNS） in relation to different addictive drugs （methamphetamine, heroin and their mixture） in drug-addicted rat models.

Central monoaminergic systems are a site of convergence of signals conveying the experience of exercise to brain circuits involved in cognition and emotional behavior

Physical activity can enhance cognitive function and increase resistance against deleterious effects of stress on mental health. Enhanced cognitive function and stress resistance produced by exercise are conserved among vertebrates, suggesting that ubiquitous mechanisms may underlie beneficial ef- fects of exercise. In the current review, we summarize the beneficial effects of exercise on cognitive function and stress resistance and discuss central and peripheral signaling factors that may be critical for conferring the effects of physical activity to brain circuits involved in cognitive function and stress. Additionally, it is suggested that norepinephrine and serotonin, highly conserved monoamines that are sensitive to exercise and able to modulate behavior in multiple species, could represent a conver- gence between peripheral and central exercise signals that mediate the beneficial effects of exercise. Finally, we offer the novel hypothesis that thermoregulation during exercise could contribute to the emotional effects of exercise by activating a subset of temperature-sensitive serotonergic neurons in the dorsal raphe nucleus that convey anxiolytic and stress-protective signals to forebrain regions. Throughout the review, we discuss limitations to current approaches and offer strategies for future re- search in exercise neuroscience.

Solution-processable graphenes by covalent functionalization of graphene oxide with polymeric monoamines

We develop here a simple wet chemistry to prepare covalent functionalized graphenes （FGs） through epoxide aminolysis espe- cially under alkaline aqueous condition. Remarkably, a series of typical monoamines, such as industrial Huntsman Jeffamine M-2070 and M-2005 polymer with hydrophilic or hydrophobic polyetheramine chains, positively-charged 2-amino-N,N,N- trimethylpropanaminium, negatively-charged sulfanilic acid, even oligopeptide sequence, can be effectively grafted on the platelets of graphene oxide precursor with covalent functionalization and partially reduced features. This strategy provides the researchers a facile and convenient approach to design and synthesize solution processable, biocompatible and functionalized graphenes for the potent applications in electronic inks, drug carriers and biomedicines. Expansion of the current study is actively ongoing in our laboratory.

The organization of societal conflicts by pavement ants Tetramorium caespitum： an agent-based model of amine-mediated decision making

Ant colonies self-organize to solve complex problems despite the simplicity of an individual ant＇s brain. Pavement ant Tetramorium caespitum colonies must solve the problem of defending the ter- ritory that they patrol in search of energetically rich forage. When members of 2 colonies randomly interact at the territory boundary a decision to fight occurs when： 1） there is a mismatch in nest- mate recognition cues and 2） each ant has a recent history of high interaction rates with nestmate ants. Instead of fighting, some ants will decide to recruit more workers from the nest to the fighting location, and in this way a positive feedback mediates the development of colony wide wars. In ants, the monoamines serotonin （5-HT） and octopamine （OA） modulate many behaviors associated with colony organization and in particular behaviors associated with nestmate recognition and ag- gression. In this article, we develop and explore an agent-based model that conceptualizes how in- dividual changes in brain concentrations of 5-HT and OA, paired with a simple threshold-based de- cision rule, can lead to the development of colony wide warfare. Model simulations do lead to the development of warfare with 91% of ants fighting at the end of 1 h. When conducting a sensitivity analysis, we determined that uncertainty in monoamine concentration signal decay influences the behavior of the model more than uncertainty in the decision-making rule or density. We conclude that pavement ant behavior is consistent with the detection of interaction rate through a single timed interval rather than integration of multiple interactions.