Differential inhibition of basal and overactivated nNOS by bis(7)-tacrine
The activity of NOS and its inhibition by different chemicals were measured in CGNs by the NOS assay kit as described under Materials and Methods. Relative inhibitory potency was expressed as [1 — (NOS activity of group with the drug at 1 μM over that of control group)] × 100%. The IC50 value of each chemical to inhibit endogenous NOS in CGNs treated with glutamate at 75 μM was obtained from eight-point titration using Sigma Plot 9.0, where each individual point was an average of duplicate determination at the same concentration from three independent experiments. Glutamate at 75 μM increased the activity of NOS by 2.7 ± 0.37-fold of the basal level.
Drug | Basal NOS (without Glutamate), Relative Inhibitory Potency at 1 μM | Activated NOS (with Glutamate) IC50 |
|---|---|---|
| % | μM | |
| Bis(7)-tacrine | 4.5 ± 0.36 | 0.03 ± 0.0061 |
| L-NMMA | 3.7 ± 0.45 | 43.6 ± 5.73 |
| Memantine | 0.8 ± 0.29 | 7.5 ± 0.96 |