Function of axonal hyperpolarization activated currents

• Applicant: Professor Dr. Stefan Hallermann
• Subject Area: Molecular Biology and Physiology of Neurons and Glial Cells
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317816582

Cerebellar mossy fibers offer the chance to analyze myelinated central axons with direct patch clamp recordings at en-passant presynaptic boutons. Cerebellar mossy fibers boutons (cMFBs) generate ultrafast action potentials (half duration 100 µs), which can occur at frequencies higher than 1 kHz. Furthermore, cMFBs exhibit a prominent hyperpolarization activated current (I_h). Despite intense research the function of I_h in the axon remains largely unclear. Therefore, cMFBs offer the unique chance to directly investigate the function of I_h in axons. In the proposed project the hypotheses will be tested that I_h facilitates the generation of high-frequency action potentials, accelerates the speed of action potential propagation, and via modulation by Epinephrine regulates the function of axons. To investigate these hypotheses advanced electrophysiological techniques will mainly be used. The expected results are of general interest and could contribute to a better understanding of diseases, in which the propagation of action potentials in axons is impaired.

• DFG Programme: Research Grants