Inflammation in VTA Caused by HFD Induces Activation of Dopaminergic Neurons Accompanied by Binge-like Eating.

Binge eating is a characteristic symptom observed in obese individuals that is related to dysfunction of dopaminergic neurons (DNs). Intermittent administration of a high-fat diet (HFD) is reported to induce binge-like eating, but the underlying mechanisms remain unclear. We generated dopaminergic neuron specific IKKß deficient mice (KO) to examine the effects of inflammation in DNs on binge-like eating under inflammatory conditions associated with HFD. After administration of HFD for 4 weeks, mice were fasted for 24 h, and then the consumption of HFD was measured for 2 h. We also evaluated that the mRNA expressions of inflammatory cytokines, glial markers, and dopamine signaling-related genes in the ventral tegmental area (VTA) and striatum. Moreover, insulin was administered intraventricularly to assess downstream signaling. The consumption of HFD was significantly reduced, and the phosphorylation of AKT in the VTA was significantly increased in female KO compared to wild-type (WT) mice. Analyses of mRNA expressions revealed that DNs activity and inflammation in the VTA were significantly decreased in female KO mice. Thus, our data suggest that HFD-induced inflammation with glial cell activation in the VTA affects DNs function and causes abnormal eating behaviors accompanied by insulin resistance in the VTA of female mice.

Rapid and direct compositional analysis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in whole bacterial cells by thermally assisted hydrolysis and methylation-gas chromatography.

Thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of an organic alkali was applied to the direct analysis of copolymer composition for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] accumulated in whole bacterial cells. Cupriavidus necator was grown on a liquid medium with different molar ratios of valeric acid (V) to glucose (G) in order to control the compositions of P(3HB-co-3HV) produced in the cells. Trace amounts (0.03 mg) of dried Cupriavidus necator cells were directly subjected to THM-GC in the presence of tetramethylammonium hydroxide (TMAH) at 400°C. The obtained chromatograms clearly showed nine characteristic peaks, attributed to the THM products from 3HB and 3HV units in the polymer chains, without any appreciable interference by the bacterial matrix components. Based on these peak intensities, the copolymer compositions were determined rapidly without using any cumbersome sample pretreatment. Moreover, the compositions thus obtained were in good agreement with those obtained by the conventional technique.