Fig. 7. Content of cyclic guanosine 3′,5′-monophosphate (cGMP) in the dorsal half of the lumbar spinal cord. Control = perfusion of artificial cerebrospinal fluid alone; NMDA = perfusion of N -methyl-D-aspartate (1.0 mM); L-NMMA = perfusion of N G-monomethyl-L-arginine acetate (10 mM) for 40 min; L-NMMA + NMDA = L-NMMA (10 mM) for 40 min with coperfusion of NMDA (1.0 mM) for the last 10 min. Data are presented as mean ± SD (n = 6–8). * P < 0.01 vs. control.