EFFECTS OF SODIUM-NITROPRUSSIDE ON THE CATECHOLAMINE SYNTHETIC PATHWAY IN THE ADRENAL-MEDULLA OF RATS

We studied the effect of sodium nitroprusside (SNP), a nitric oxide (N O) donor, on tyrosine hydroxylase (TH) activity and epinephrine and no repinephrine levels in the adrenal medulla of rats. TH activity and th e levels of epinephrine and norepinephrine in the adrenal medulla of t he SNP+nicotine (Nic)-treated group were increased significantly compa red to those in the control, Nic-treated and SNP-treated groups. Furth ermore, methylene blue inhibited this increase in TH activity. The dat a suggest that the NO derived from SNP may increase TH through the gua nylyl cyclase pathway in the presence of Nic.