Fig. 4. (A) 7 DIV granule cells synthesize cGMP in response to NMDA. Cells subjected to different conditions (1 hour incubation with 1 mM L-NAME, 30 minutes incubation with 10 µM ODQ, 30 minutes incubation in a calcium-free medium, 10 minutes incubation with 50 µM AP5, 1 µM MK-801 or 5 µM MK-801) were preincubated with IBMX for 30 minutes and then stimulated for 10 minutes with 100 µM NMDA. Results are expressed as pmol/10⁶ cells and correspond to the mean ± s.e.m. of three experiments performed in triplicate using different cultures. Significant differences from controls are indicated as: ^***P<0.001 (NMDA-stimulated).