Excess sympathetic nervous system activity (SNA) is linked to human essential and experimental
hypertension. To test whether sympathetic activation is associated with a model of
deoxycorticosterone acetate (
DOCA)-
salt hypertension featuring two kidneys and a moderate elevation of blood pressure, we measured whole body
norepinephrine (NE) spillover as an index of global SNA. Studies were conducted in chronically catheterized male Sprague-Dawley rats
drinking water containing 1% NaCl and 0.2% KCl. After a 7-day surgical recovery and a 3-day control period, a
DOCA pellet (50 mg/kg) was implanted subcutaneously in one group of rats (
DOCA), while the other group underwent
sham implantation (
Sham). NE spillover was measured on control day 2 and days 7 and 14 after
DOCA administration or
sham implantation. During the control period, mean arterial pressure (MAP) was similar in
Sham and
DOCA rats. MAP was significantly increased in the
DOCA group compared with the
Sham group after
DOCA administration (day 14:
Sham = 109 ± 5.3,
DOCA = 128 ± 3.6 mmHg). However, plasma NE concentration, clearance, and spillover were not different in the two groups at any time. To determine whether selective sympathetic activation to the kidneys contributes to
hypertension development, additional studies were performed in renal denervated (
RDX) and
sham-denervated (
Sham-DX) rats. MAP, measured by radiotelemetry, was similar in both groups during the control and
DOCA treatment periods. In conclusion, global SNA is not increased during the development of mild
DOCA-
salt hypertension, and fully intact renal nerves are not essential for
hypertension development in this model.