OBJECTIVE：To study the effcet of Nitric oxide (No) on transcriptional expression of c-fos and c-jun oncogene of cultured rabbit arterial smooth muscle cells (ASMC),and its mechanism.METHODS:(1)To culture rabbit ASMC from explants;(2) To determine if NO,FeSO4,and methylene blue have toxic effect on ASMC by cell counting;(3)RNA isolation from ASMC by Guanidinium Thiocyanate-phenol-chloroform method;(4)RNA-DNA blot hybridization.RESULTS:Under the condition of no toxic effects,NO inhibited the expression of c-fos and c-jun oncogene of ASMC apparently,FeSO4 and methylene blue antagonized the inhibition effcet.CONCLUSION:NO inhibited the expression of c-fos and c-jun oncogene of ASMC through cGMP.This may be related to the important mechanism that NO inhibits the proliferation of ASMC.