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

Figure 4

An enzymatic treatment of MTX (100 mg/mL) by trypsin resulted in a reduction of the peptide-mediated neuroprotection of AMPARs and NMDARs in slices of rat olfactory cortex. The dashed lines in (a) and (b) show control level of the AMPA and NMDA EPSP amplitudes. On the abscissa: control: the averaged values of the AMPA and NMDA EPSP amplitudes performed during 15 min; “Glu, ctrl”: effect of L-glutamate in toxic concentration 20 mM during 20 min; “Glu + MTX treat.”: effects of L-glutamate in toxic concentration 20 mM and subsequent action of the MTX pretreated during 25 min; and “wash”: washout, 20 min. The data are expressed as percentage of control value and represent means ± SEM analyzed statistically by -test, Wilcoxon-Mann-Whitney matched pairs signed-rank test. , significantly different from control. , number of slices per column. Statistically significant differences as compared to control are indicated by asterisks; -test, . for every point. Note that the enzymatic pretreatment of MTX resulted in a decrease (statistically insignificant) in the amplitudes of AMPA EPSP but does not completely block theirs. The same values of responses persisted after washout. Hyperactivity of NMDARs to glutamate action and subsequent treatment of slices by MTX significantly decreased but remained increased compared with the control level.

(a)

(b)