Gudbjornsdottir S, Lonnroth P, Bergmann-Sverrisdottir Y,
Gunnar-Wallin B, Elam M
Sympathetic nerve activity and insulin in obese
normotensive and hypertensive men
Hypertension
(Feb) 27:276-280 1996

For original abstract, click here.
The relationship between obesity, insulin resistance, and
hypertension is now well established, although the mechanisms
remain a subject of controversy. Elevated muscle sympathetic nerve
activity (MSA), as measured by electrodes attached to the peroneal
nerve, has been demonstrated in several subsets of hypertensive
patients, including patients with ESRD and those taking
cyclosporine. In this study, MSA was compared in 18 obese white
hypertensive males vs. 16 age-matched normotensive controls, to
determine whether or not the hypertension associated with obesity
is also associated with elevated MSA.
To make a short story even shorter: no increase in MSA activity was found in
obese hypertensives
vs. controls, contradicting several earlier studies that suggested MSA is
indeed elevated in such
hypertensives.
Comment: Although the study is presented as negative, there
was a correlation, in hypertensives only, between body mass index
(BMI) and MSA, and also between fasting plasma insulin levels in
MSA. In fact, in normotensives, the as BMI or plasma insulin
levels increased, MSA tended to decrease, whereas in hypertensives,
a clear, statistically significant upward trend was found. So this
study may not be completely negative after all, although given the
small magnitude of the differences in MSA found, mechanisms other
than increased MSA must be
invoked to explain the hypertension associated with obesity and
insulin resistance.
(John T. Daugirdas, M.D., University of Illinois at Chicago)