Mathematical modeling of the biphasic dopaminergic response to glucose


In this work, we specify potential elements of the brain to sense and regulate the energy metabolism of the organism. Our numerical investigations base on neurochemical experiments demonstrating a biphasic association between brain glucose level and neuronal activity. The dynamics of high and low affine KATP channels are most likely to play a decisive role in neuronal activity. We develop a coupled Hodgkin-Huxley model describing the in-teractive behavior of inhibitory GABAergic and excitatory dopaminergic neurons projecting into the caudate nucleus. The novelty in our approach is that we include the synaptic coupling of GA BAergic and dopaminergic neurons as well as the interac-tion of high and low affine KATP channels. Both are crucial mechanisms described by kinetic models. Simulations demonstrate that our new model is co-herent with neurochemical in vitro experiments. Even experimental interventions with glibencla-mide and glucosamine are reproduced by our new model. Our results show that the considered dy-namics of high and low affine KATP channels may be a driving force in energy sensing and global reg-ulation of the energy metabolism, which supports central aspects of the new Selfish Brain Theory. Moreover, our simulations suggest that firing fre-quencies and patterns of GABAergic and dopa-minergic neurons are correlated to their neuro-chemical outflow.

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