Although
atherosclerosis causes a marked inhibition of the endothelium-dependent vasorelaxation it also leads to expression of
inducible nitric oxide synthase (iNOS), accompanied by an increase in
cyclic GMP content, in the arterial wall. The aim of our present study as to evaluate the influence of
atherosclerosis on the
soluble guanylyl cyclase pathway in viable cultured smooth muscle cells (SMC) from rabbit atherosclerotic rabbit aortas (atherosclerotic SMC) and from control rabbit aortas (control SMC). In response to 100 microM
sodium nitroprusside (SNP), the intracellular production of
cyclic GMP was similar in both types of cells, reaching a maximum after 5 min of incubation. In the culture medium, SNP evokes an increased
cyclic GMP concentration lasting 6 h in control SMC and 24 h in atherosclerotic SMC.
Interleukin-1beta (100 IU/mL), which induces iNOS in SMC from both control and atherosclerotic aortas causes accumulation of cyclic GMIP in the extracellular medium between 3 and 6 h for control SMC and between 3 and 24 h with atherosclerotic SMC. These results demonstrate a long-lasting egression of
cyclic GMP in the extracellular medium of cultured SMC from rabbit aortas in response to endogenous or exogenous NO. Since this egression of
cyclic GMP lasts longer in atherosclerotic than in control SMC, we suggest that
atherosclerosis dysregulates the long-term
soluble guanylyl cyclase response to NO in SMC.