7-nitroindazole, a selective neuronal nitric oxide synthase inhibitore in vivo, prevents kainate-induced intrahippocampal neurotoxicity

Modulation of nickel-induced bursting with 4-aminopyridine in leech retzius nerve cells

Paroxysmal depolarization shift has been identified as a characteristic feature of the cellular basis of epilepsy. On Na+-dependent bursting, 1 mmol/l 4-aminopyridine (4-AP) produced a two-phase effect - a significant depolarization accompanied by an increase in the frequency of bursting, followed by repolarization along with a diminished frequency of bursting. Neither 1 ?mol/l apamin nor 150 nmol/l charybdotoxin (ChTX) elicited any significant effect on either bursting or standard conditions. Our results suggest that 4-AP affects the bursting indirectly by altering the excitability of the cell. The lack of effects of apamin and ChTX is probably due to channel insensitivity to these blockers in leech.

Effect of 7-nitroindazoleon superoxide production and MnSOD activity in threat brain following kainate-induced neurotoxicity

We investigated the effect of 7-nitroindazole (7-NI), a selective neuronal nitric oxide synthase inhibitor in vivo, on superoxide concentration as well its influence on mitochondrial MnSOD activity since this activity is associated with the production of reactive oxygen species after kainate-induced neurotoxicity. The time course of in vivo oxidative damage in different brain regions was investigated. Measurements were performed at different times (5 min, 15 min, 2 h, 48 h, and 7 days) in the ipsi- and contralateral hippocampus, forebrain cortex, striatum, and cerebellum homogenates. Our results indicated that 7-NI had no statistically significant influence on superoxide concentrations in the tested brain structures compared to the control values. However, superoxide concentrations after kainate-induced neurotoxicity returned to the control values after pretreatment with 7-NI in all tested brain structures. Regarding the activity of MnSOD, our results demonstrated statistically significant increase 7 days after intrahippocampal KA treatment in all tested brain structures after pretreatment with 7-NI. The obtained results suggest that neuronal NO synthase inhibitors may be useful in the treatment of neurological diseases in which excitotoxic mechanisms play a role. <br><br><font color="red"><b> This article has been retracted. Link to the retraction <u><a href="http://dx.doi.org/10.2298/ABS150330033E">10.2298/ABS150330033E</a><u></b></font>