Mechanosensitivity in the enteric neuronal Network
Enteric neurons lie in the gut wall and are therefore continuously exposed to mechanical stress. Following a current concept, a spezialized group of neurons (IPAN - intrinsic primary afferent neurons) is functioning as sensors for these mechanical stimuli. The information is then further processed by other groups of enteric neurons (Inter-, Motorneurons) and finally used to generate the appropriate motor patterns. In contrast to this concept we have been able to identify multifunctional enteric neurons which respond to mechanical stimuli. These neurons have been termed by us multifunctional "Rapidly Adapting Mechanosensitive Enteric Neurons" (RAMEN).
The aim of our current project is to further characterize RAMEN in order to clarify the sensory detection modalities of the mechanical stimuli and the pathways through the enteric nervous system control peristalsis.
The technique applied is an ultrafast neuroimaging technique based on a voltage sensitive dye. Mechanical stimulations are performed with state of the art methods. Experiments are done on samples of guinea pig and mouse intestine or on primary culture of human and guinea pig enteric neurons.
Identification and characterization of the pathways that regulate mechanosensitivity and of the enteric neurons role in the regulation of peristalsis is important to understand the gut behaviour in normal as well as pathological conditions and to identify novel targets that help to normalise sensory-motor impaired functions.
Funded by: Deutsche Forschungsgemeinschaft (DFG MA 5202/1-1).
Mechanosensitivity of an enteric neuron, measured with a membrane potential sensitive dye (see Neuro-Imaging). The neuron is probed with a fine filament ("von Frey hair") and responds with a train of action potentials (lower part of the picture). Clicking on the picture loads a movie in which the changes in the membrane potential are color coded. For clarification only action potentials are shown (in red).