AMPA receptor-evoked increases in intracellular Ca2+ are insensitive to the protein kinase inhibitors KN-62, PD 98059, and genistein, and the lipid kinase inhibitor wortmannin
| Treatments | 340 nm/380 nm ratio change (20 sec after stimulation) |
|---|---|
| AMPA | 0.37 ± 0.056 (6) |
| AMPA/Cyz | 1.04 ± 0.071 (54) |
| AMPA/Cyz + GYKI 53655 | 0.073 ± 0.017 (12)* |
| AMPA/Cyz + KN-62 | 0.96 ± 0.058 (36) |
| AMPA/Cyz + PD 98059 | 0.84 ± 0.048 (18) |
| AMPA/Cyz + genistein | 1.00 ± 0.069 (14) |
| AMPA/Cyz + wortmannin | 1.13 ± 0.10 (36) |
Fura-2-loaded striatal neurons were preincubated for 5 min in the presence of 5 μm KN-62, 50 μm PD 98059, 50 μm genistein, or 100 nm wortmannin, before the addition of 50 μm AMPA in the presence of 50 μm cyclothiazide (AMPA/Cyz) to evoke Ca2+influx. Fura-2 fluorescence was monitored as described in the Materials and Methods, and increases in the fura-2 fluorescence (340 nm/380 nm ratio) 20 sec after the addition of agonist are shown. Responses to AMPA (50 μm) alone and to AMPA/Cyz (50 μm/50 μm) in the presence of 100 μm GYKI 53655 (added 5 min before AMPA/Cyz) are included for comparison. Results are means ± SEM of responses from the number of neurons (n) measured.
*AMPA/Cyz + GYKI 53655 was significantly different from AMPA/Cyz (p < 0.001, unpaired two-tailed Student’st test). No significant differences were found between AMPA/Cyz and AMPA/Cyz in the presence of any of the kinase inhibitors tested.