EFFECT OF DIETARY NACL ON TYROSINE-HYDROXYLASE IN THE SUPERIOR CERVICAL-GANGLIA OF DAHL RATS

To investigate the involvement of peripheral catecholamines in the dev elopment of Dahl-Iwai salt-sensitive (DIS/Eis) hypertension, we perfor med immunohistochemical staining of tyrosine hydroxylase (TH) in the s uperior cervical ganglia (SCG) of DIS/Eis rats and Dahl-Iwai salt-resi stant (DIR/Eis) rats, and in situ hybridization histochemistry for dem onstration of TH mRNA localization in the SCG of these rats. DIS/Eis a nd DIR/Eis rats were fed on a high (8%) salt diet or on a low (0.3%) s alt diet for 4 weeks. Nerve cells in the SCG of DIS/Eis high salt rats exhibited more intense TH-immunoreactivity (P < 0.01) and hybridizati on signals (P < 0.01) than those of the other experimental groups. The se findings suggest that activation of peripheral sympathetic nerves m ay account for hypertension in DIS/Eis rats on a high salt diet.