Cav3.1-driven bursting firing in ventromedial hypothalamic neurons exerts dual control of anxiety-like behavior and energy expenditure.

The central nervous system has evolved to coordinate the regulation of both the behavior response to the external environment and homeostasis of energy expenditure. Recent studies have indicated the dorsomedial ventromedial hypothalamus (dmVMH) as an important hub that regulates both innate behavior and energy homeostasis for coping stress. However, how dmVMH neurons control neuronal firing pattern to regulate chronic stress-induced anxiety and energy expenditure remains poorly understood. Here, we found enhanced neuronal activity in VMH after chronic stress, which is mainly induced by increased proportion of burst firing neurons. This enhancement of VMH burst firing is predominantly mediated by Cav3.1 expression. Optogenetically evoked burst firing of dmVMH neurons induced anxiety-like behavior, shifted the respiratory exchange ratio toward fat oxidation, and decreased food intake, while knockdown of Cav3.1 in the dmVMH had the opposite effects, suggested that Cav 3.1 as a crucial regulator. Interestingly, we found that fluoxetine (anxiolytics) could block the increase of Cav3.1 expression to inhibit the burst firing, and then rescued the anxiety-like behaviors and energy expenditure changes. Collectively, our study first revealed an important role of Cav3.1-driven bursting firing of dmVMH neurons in the control of anxiety-like behavior and energy expenditure, and provided potential therapeutic targets for treating the chronic stress-induced emotional malfunction and metabolism disorders.

Effect of carbonate on anaerobic acidogenesis and fermentative hydrogen production from glucose using leachate as supplementary culture under alkaline conditions.

Carbonate was added into a co-culture of glucose and fresh leachate under alkaline condition to enhance batched acidogenesis and fermentative hydrogen production simultaneously. Results indicated carbonate has positive effect on both H(2) production and acetic acid generation. The highest hydrogen yield (about 1.40 mol/mol glucose) was obtained at [CO(3)(2-)] = 280 mg/L with pH 8.0 and [CO(3)(2-)] = 560 mg/L with pH 9. The dominant liquid metabolites were ethanol, acetic and butyric acid. The highest total volatile fatty acid yield (0.38 g/g glucose) was achieved at [CO(3)(2-)] = 560 mg/L with pH 9. In this case, the acetic acid yield reached 0.13 g/g glucose. Verification tests using simulated wastewater as substrate were also carried out at pH 9. Results demonstrated calcium ions inhibit hydrogenogens activity while carbonate addition can alleviate the suppression effect caused by Ca(2+).