Low-Dose Sevoflurane Promotes Hippocampal Neurogenesis and Facilitates the Development of Dentate Gyrus-Dependent Learning in Neonatal Rats

Sugar has become embedded in modern food and beverages. This has led to overconsumption of sugar in children, adolescents, and adults, with more than 60 countries consuming more than four times (>100 g/person/day) the WHO recommendations (25 g/person/day). Recent evidence suggests that obesity and impulsivity from poor dietary habits leads to further overconsumption of processed food and beverages. The long-term effects on cognitive processes and hyperactivity from sugar overconsumption, beginning at adolescence are not known. Using a well-validated mouse model of sugar consumption, we found that long-term sugar consumption, at a level that significantly augments weight gain, elicits an abnormal hyperlocomotor response to novelty and alters both episodic and spatial memory. Our results are similar to those reported in attention deficit and hyperactivity disorders. The deficits in hippocampal-dependent learning and memory were accompanied by altered hippocampal neurogenesis, with an overall decrease in the proliferation and differentiation of newborn neurons within the dentate gyrus. This suggests that long-term overconsumption of sugar, as that which occurs in the Western Diet might contribute to an increased risk of developing persistent hyperactivity and neurocognitive deficits in adulthood.

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Metabolic tuning of inhibition regulates hippocampal neurogenesis in the adult brain

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2006138117 ◽

2020 ◽

Vol 117 (41) ◽

pp. 25818-25829

Author(s):

Xinxing Wang ◽

Hanxiao Liu ◽

Johannes Morstein ◽

Alexander J. E. Novak ◽

Dirk Trauner ◽

...

Keyword(s):

Dentate Gyrus ◽

Energy Homeostasis ◽

Inhibitory Neuron ◽

Hippocampal Neurogenesis ◽

Adult Brain ◽

Adult Hippocampal Neurogenesis ◽

Neuron Activity ◽

Adult Mice ◽

Sphingosine 1 Phosphate ◽

Underlying Mechanisms

Hippocampus-engaged behaviors stimulate neurogenesis in the adult dentate gyrus by largely unknown means. To explore the underlying mechanisms, we used tetrode recording to analyze neuronal activity in the dentate gyrus of freely moving adult mice during hippocampus-engaged contextual exploration. We found that exploration induced an overall sustained increase in inhibitory neuron activity that was concomitant with decreased excitatory neuron activity. A mathematical model based on energy homeostasis in the dentate gyrus showed that enhanced inhibition and decreased excitation resulted in a similar increase in neurogenesis to that observed experimentally. To mechanistically investigate this sustained inhibitory regulation, we performed metabolomic and lipidomic profiling of the hippocampus during exploration. We found sustainably increased signaling of sphingosine-1-phosphate, a bioactive metabolite, during exploration. Furthermore, we found that sphingosine-1-phosphate signaling through its receptor 2 increased interneuron activity and thus mediated exploration-induced neurogenesis. Taken together, our findings point to a behavior-metabolism circuit pathway through which experience regulates adult hippocampal neurogenesis.

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Correlations between Hippocampal Neurogenesis and Metabolic Indices in Adult Nonhuman Primates

Neural Plasticity ◽

10.1155/2011/875307 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 21

Author(s):

Tarique D. Perera ◽

Dunyue Lu ◽

Lakshmi Thirumangalakudi ◽

Eric L. P. Smith ◽

Arkadiy Yaretskiy ◽

...

Keyword(s):

Dentate Gyrus ◽

Nonhuman Primates ◽

Density Lipoprotein ◽

B Cell Lymphoma ◽

Hippocampal Neurogenesis ◽

Metabolic Parameters ◽

Crown Rump Length ◽

Neuronal Marker ◽

Bonnet Macaques ◽

Metabolic Indices

Increased neurogenesis in feeding centers of the murine hypothalamus is associated with weight loss in diet-induced obese rodents (Kokoeva et al., 2005 and Matrisciano et al., 2010), but this relationship has not been examined in other species. Postmortem hippocampal neurogenesis rates and premortem metabolic parameters were statistically analyzed in 8 chow-fed colony-reared adult bonnet macaques. Dentate gyrus neurogenesis, reflected by the immature neuronal marker, doublecortin (DCX), and expression of the antiapoptotic gene factor, B-cell lymphoma 2 (BCL-2), but not the precursor proliferation mitotic marker, Ki67, was inversely correlated with body weight and crown-rump length. DCX and BCL-2 each correlated positively with blood glucose level and lipid ratio (total cholesterol/high-density lipoprotein). This study demonstrates that markers of dentate gyrus neuroplasticity correlate with metabolic parameters in primates.

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