Central attenuation of baroreflex precedes the development of hypertension in DOCA-salt-treated rats.

To determine whether baroreflex is changed centrally before the development of hypertension in DOCA-salt treated rats, aortic depressor nerve was stimulated electrically 5 days after DOCA-salt treatment in urethane-anesthetized rats: compared with those of sham-operated control rats, blood pressure was not elevated in either awake or anesthetized rats. Aortic depressor nerve (ADN) stimulation elicited frequency-dependent vasodepressor, bradycardiac, and sympatho-inhibitory responses in both DOCA-salt-treated and control rats. However, the responses to ADN stimulation were significantly smaller in DOCA-salt-treated rats. These findings suggest that baroreflex is attenuated centrally before the development of hypertension and this attenuation may contribute to the pathogenesis of DOCA-salt hypertension.