will take place on Tuesday, May 14, 2019 from 17:15 to 18:15 hours in CBBM, Ground Floor, Seminar Room B1/B2.
Host: Prof. Dr. Markus Schwaninger
Institute of Pharmacology and Toxicology
University of Lübeck
Abstract
Feeding constitutes a complex behaviour that aims to satisfy the energetic needs of organisms in order to fuel crucial basic metabolic processes and behaviours ensuring individual and species survival. Substantial efforts in recent decades led to defining the neuronal networks in the hypothalamus that regulate homeostatic feeding. In the arcuate nucleus of the hypothalamus (ARH), two functional antagonistic populations are located that have opposing effects on feeding behaviour. Upon activation, AgRP (agouti-related peptide)-expressing neurons increase food intake while decreasing energy expenditure. In contrast, activation of POMC (proopiomelanocortin)-expressing cells promote decreased food intake and an increase in energy expenditure. Importantly, these cells are the targets for many central and peripheral signals that communicate the organism’s energy state. In our research, we are specifically interested in the short-term modulation of this network by transmitters and neuromodulators as well as in the effects of long-term modulation on these cells, such as exposing the animals to a chronic high-fat diet.
We recently identified the catecholamine noradrenalin, which is released by nuclei in the brainstem, to target AgRP and POMC neurons in the ARH. While many studies indicated a role of NA in the control of food intake, this illustrates for the first time a direct modulation of identified cells, known to control energy homeostasis. Thus, the coordinated differential modulation of these key hypothalamic neurons assigns noradrenalin an important role to promote feeding. While these data expand the view of the control of food intake and energy expenditure, we are also interested in the effect of HFD feeding on the intrinsic electrophysiological properties of these cell. Further, we uncovered a mechanism how HFD feeding contributes to silencing of satiety signalling POMC neurons by impairing Ca2+ handling in these cells, resulting in the activation of Ca2+ - dependent K+-channels.
Bioskecth
Lars studied biology at the University of Cologne. As an electrophysiologist, he started working in the field of the insect olfactory system analyzing ionic currents that shape the intrinsic excitability of cells involved in the processing of olfactory information. After receiving his diploma, he started working in the “neuronal control of energy homeostasis” in mice in close collaboration with the Max-Planck-Institute for Metabolism Research in Cologne. After obtaining his PhD and working as a postdoc he received a postdoctoral fellowship for metabolism research funded by Novo Nordisk at the Karolinska Institutet in Stockholm, Sweden. His main research interest are:
- the intrinsic electrophysiological properties of neurons involved in energy homeostasis and how they are altered by chronic dietary changes and ageing
- the role of the locus coeruleus and the catecholamine noradrenalin in the control of food intake and energy expenditure
- the role of the somatostatin-growth hormone axis in the control of energy metabolism
