Institute of Zoology, Faculty of Math. Nat. Sciences
Obesity and type 2 diabetes are closely linked diseases that are associated with excessive weight and fat mass, and their prevalence is increasing within Western populations. The goal of Prof. Dr. Kloppenburg and his group is to define the mechanisms that regulate body weight and energy homeostasis, and look at how these control mechanisms change under pathophysiological conditions that promote hyperphagia.
Our research: Energy homeostasis is tightly controlled by defined neuronal circuits in the brain to adjust food intake and energy expenditure according to the availability of fuel sources in the periphery of the body. Aging, extreme diets, and diseases can deregulate these neuronal systems. To understand what makes organisms susceptible to metabolic disorders, it is essential to define age and diet-associated changes in this network.
Our successes: The group has shown that high caloric diet-induced obesity can cause functional and structural changes in the adult neuronal networks that control food intake. Another important finding was that a maternal high-fat diet during lactation impaired the proper formation of these circuits in the offspring.
Our goals: One of the Kloppenburg team’s main aims is to define the biophysical parameters and cellular mechanisms that cause age- and diet-dependent changes in the intrinsic firing characteristics and synaptic properties of the neuronal circuits that control energy homeostasis. A detailed understanding of the mechanisms that promote or prevent deregulation of these neuronal control circuits may lead to novel approaches for therapeutic intervention in metabolic and neurological disorders.
Our methods/techniques: To achieve these goals, the laboratory is using a combination of various electrophysiological and optophysiological recording techniques.
Figure 1: The figure shows a midbrain dopaminergic neuron and its electrophysiological response to insulin. Elevation of the extracellular insulin concentration increases the action potential frequency. The top panel shows the relative change over time. The lower panels display original traces before and during insulin administration.
Figure 2: Midbrain dopaminergic neurons integrate signals on food palatability and food-associated reward into the complex control of energy homeostasis. Insulin is a peptide hormone that is part of the metabolic pathway regulating the nutrient concentration in the blood.