Aim To observe the effect of protein-tyrosine kinases (PTKs) and protein kinase C (PKC) on expression of inducible nitric oxide synthase (iNOS) gene in vascular smooth muscle cells (VSMC). Methods Cultured aortic VSMC of normal SD rat were used to investigate iNOS mRNA expression which was analysed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). According to the principle of Griess reaction, nitrite was determined from the supernatant of cultured VSMC to estimate the nitric oxide (NO) release. Results Protein-tyrosine kinases inhibitor can significantly inhibit VSMC iNOS mRNA expression (0.830±0.189 vs 0.519±0.180, P<0.05)and nitrite accumulation in medium (8.94±0.86 μmol/L vs 2.83±0.47 μmol/L, P<0.01) induced by interleukin 1β(IL-1β). Depleted PKC had no effects on VSMC iNOS mRNA expression (0.83±0.189 vs 0.815±0.174,P>0.05) and nitrite accumulation in medium (8.94±0.86 μmol/L vs 8.36±0.56 μmol/L, P>0.05). Conclusion Signal transduction of VSMC iNOS gene expression induced by IL-1βis PTKs dependent and PKC independent. 还原