Mystixin-7 Peptide Protects Ionotropic Glutamatergic Mechanisms against Glutamate-Induced Excitotoxicity In Vitro

Hyperactivation of the N-methyl-D-aspartic acid type glutamate receptors (NMDARs) causes glutamate excitotoxicity, a process potentially important for many neurological diseases. This study aims to investigate protective effects of the synthetic corticotrophin-releasing factor-like peptide, mystixin-7 (MTX), on model glutamate-induced excitotoxicity in vitro. The technique online monitoring of electrophysiological parameters (excitatory glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPAR) and NMDAR-dependent postsynaptic mechanisms) in the olfactory cortex slices was used. Application of L-glutamate in toxic concentration (20 mM) on slices evoked hyperactivation of NMDARs and weaker activation of the AMPARs. Upon further action agonist, the excessive activation of glutamate receptors was replaced by their irreversible blockade. Pretreatment of the slices using MTX in different concentrations (50 and 100 mg/mL) protected both NMDARs and AMPARs from glutamate-induced damage. An enzymatic treatment of MTX reduced hyperactivation of both NMDARs and AMPARs. The present study demonstrated that MTX minipeptide protected the functioning of both NMDARs and AMPARs against glutamate-induced damage. The MTX peptide is a prospective candidate for elaborated medication in treatment of neurological diseases.