Pyrrolidine dithiocarbamate selectively prevents the expression of the inducible nitric oxide synthase in the rat aorta.

Exposure of rat aortic rings without endothelium to interleukin-1 beta for 5 h significantly attenuated the contractions due to phenylephrine and increased the tissue content of guanosine 3',5'-cyclic monophosphate (cyclic GMP) due to the induction of nitric oxide synthase. The presence of pyrrolidine dithiocarbamate, a specific inhibitor of nuclear transcription factor kappa B activation, during the exposure of the rings to interleukin-1 beta prevented these responses to interleukin-1 beta. Rat aortic rings which had been incubated for 5 h with interleukin-1 beta in the absence and presence of pyrrolidine dithiocarbamate prior to the organ chamber experiment had a similar concentration-dependent relaxation curve for acetylcholine in rings with endothelium, and for 3-morpholino-sydnonimine (SIN-1) in rings without. Pyrrolidine dithiocarbamate applied acutely did not alter the tone elicited by phenylephrine in rings with or without endothelium and had no effect on the subsequent relaxation induced by acetylcholine in rings with endothelium or by SIN-1 in rings without endothelium. These observations suggest that pyrrolidine dithiocarbamate prevents the interleukin-1 beta-mediated expression of the inducible nitric oxide synthase without affecting the activity of the constitutive enzyme in the rat aorta.