Anhedonia is the inability to experience pleasure from rewarding or enjoyable activities and is a core symptom of depression in humans. Here, we describe a protocol for the measurement of anhedonia in mice, in which anhedonia is measured by a sucrose preference test (SPT) based on a two-bottle choice paradigm. A reduction in the sucrose preference ratio in experimental relative to control mice is indicative of anhedonia. To date, inconsistent and variable results have been reported following the use of the SPT by different groups, probably due to the use of different protocols and equipment. In this protocol, we describe how to set up a clearly defined apparatus for SPT and provide a detailed protocol to ensure greater consistency when carrying out SPT. This optimized protocol is highly sensitive, reliable, and adaptable for evaluation of chronic stress-related anhedonia, as well as morphine-induced dependence. The whole SPT, including adaptation, baseline measurement, and testing, takes 8 d.
In this study, a series of Fe3+ modified Amberlyst-15 resins (Fe/AR) were prepared and used as environmentally friendly bifunctional catalysts for the conversion of glucose to 5-hydroxymethylfurfural (HMF).
The {001} facet of α-Fe2O3 offered excellent activity and stability for the oxidative dehydrogenation of lactic acid to pyruvic acid due to the lower adsorption energy on its surface compared to others.
Unreactive
C–N bond activation of anilines was achieved
by photoinduced aerobic borylation. A diverse range of tertiary and
secondary anilines were converted to aryl boronate esters in moderate
to good yields with wide functional group tolerance under simple and
ambient photochemical conditions. This transformation achieved the
direct and facile C–N bond activation of unreactive anilines,
providing a convenient and practical route transforming widely available
anilines into useful aryl boronate esters.
Propionic
acid obtained from fermentation-derived lactic acid has
been appreciated since propionic acid is mainly used as a food preservative,
satisfying a natural food idea. Vapor-phase deoxygenation of lactic
acid to biopropionic acid over dispersant-dispersed molybdenum oxides
was investigated in this work. It was found that different dispersants
displayed different performances, and the N element in dispersants
had a positive effect. MoO3 was soon reduced to MoO2 under the in situ hydrogen atmosphere, and the latter played
an important role in catalytic conversion of lactic acid to propionic
acid. The discriminating experiments revealed that propionic acid
was formed mainly through direct deoxygenation of lactic acid (main
path) and not hydrogenation of acrylic acid as an intermediate (minor
path). Furthermore, only in situ hydrogen was efficient, and external
hydrogen was hardly efficient during catalytic reaction. Under the
base-free conditions, catalyst offered excellent activity and durability
and efficiently reduced the acid-treatment section in product separation.
Stress-induced depression is common worldwide. NAc, a "reward" center, is recently reported to be critical to confer the susceptibility to chronic social defeat stress (CSDS) and the depression-related outcome. However, the underlying molecular mechanisms have not been well characterized. In this study, we induced depression-like behaviors with CSDS and chronic mild stress in male mice to mimic social and environmental factors, respectively, and observed animal behaviors with social interaction test, tail suspension test, and sucrose preference test. To determine the role of neuronal nitric oxide synthase (nNOS) and its product nitric oxide (NO), we used brain region-specifically nNOS overexpression and stereotaxic injection of NO inhibitor or donor. Moreover, the downstream molecular cyclin-dependent kinase 5 (CDK5) was explored by conditional KO and gene mutation. We demonstrate that nNOS-implicated mechanisms in NAc shell (NAcSh), including increased cell number, increased protein expression levels, and increased specific enzyme activity, contribute the susceptibility to social defeat and the following depression-like behaviors. NAcSh nNOS does not directly respond to chronic mild stress but facilitates the depression-like behaviors. The increased NAcSh nNOS expression after CSDS leads to the social avoidance and depression-like behaviors in defeated mice, which is dependent on the nNOS enzyme activity and NO production. Moreover, we identify the downstream signal in NAcSh. S-nitrosylation of CDK5 by NO contributes to enhanced CDK5 activity, leading to depression-related behaviors in susceptible mice. Therefore, NAcSh nNOS mediates susceptibility to social defeat stress and the depression-like behaviors through CDK5.
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