ABSTRACT
The aim of this study was to explore the mechanism of the nervous system lesions induced by formaldehyde (FA). Male Balb/c mice were exposed to gaseous formaldehyde for 7 days (8 h/d) with three different concentrations (0, 0.5 and 3.0 mg/m(3)). A group of animals injected with the nitric oxide synthase inhibitor L-NMMA (0.01 mL/g) was also set and exposed to 3.0 mg/m(3) FA. The concentrations of cAMP, cGMP, NO and the activity of NOS in cerebral cortex, hippocampus and brain stem were determined by corresponding assay kits. The results showed that, compared with the control (0 mg/m(3) FA) group, the cAMP contents in cerebral cortex and brain stem were significantly increased in 0.5 mg/m(3) FA group (P < 0.05), but decreased in 3.0 mg/m(3) FA group (P < 0.05); The concentration of cAMP in hippocampus was significantly decreased in 3.0 mg/m(3) FA group (P < 0.05). In comparison with the control group, L-NMMA group showed unchanged cAMP contents and NOS activities in different brain regions, but showed increased cGMP contents in hippocampus and NO contents in cerebral cortex (P < 0.05). In addition, compared with 3.0 mg/m(3) FA group, L-NMMA group showed increased contents of cAMP and reduced NOS activities in different brain regions, as well as significantly decreased cGMP contents in cerebral cortex and brain stem and NO content in brain stem. These results suggest that the toxicity of FA on mouse nervous system is related to NO/cGMP and cAMP signaling pathways.