The pentapeptide QYNAD does not inhibit neuronal network activity

Introduction: Controversial data was published about the endogenous pentapeptide QYNAD, which is elevated in serum and cerebrospinal fluid of patients with demyelinating diseases like multiple sclerosis. QYNAD was made responsible for the rapid clinical fluctuations in these patients by blocking voltage-gated sodium channels of single cells with a maximum effect at a concentration of 10 micromol/l. Methods: To determine the impact of QYNAD on neuronal network activity, we used the micro-electrode array (MEA) technique. This new technique allows convenient monitoring of spontaneous electrical activity of excitabl…