Effect of angiotensin II receptor blockade on autonomic nervous system function in patients with essential hypertension.

What Was Tested

This randomized controlled trial looks at Losartan.

It has long been proposed that the renin-angiotensin system exerts a stimulatory influence on the sympathetic nervous system, including augmentation of central sympathetic outflow and presynaptic facilitation of norepinephrine release from sympathetic nerves.

The researchers tested this proposition in 19 patients with essential hypertension, evaluating whether the angiotensin receptor blockers (ARBs) eprosartan and losartan had identifiable antiadrenergic properties.

Who Took Part

The abstract describes 19 patients taking part.

The age groups tagged for this paper are teenagers, adults, middle-aged adults and older adults, both men and women.

How the Study Was Run

In design terms this was a randomized, placebo-controlled, crossover and parallel-group study.

Because people in this Losartan study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

The comparison arm used a placebo, so changes seen with Losartan could be set against what happens without it.

In the crossover set-up each of the patients took both Losartan and the comparison in turn, acting as their own control.

Groups ran in parallel: each of the patients stayed in one arm throughout.

Multiunit firing rates in efferent sympathetic nerves distributed to skeletal muscle vasculature (muscle sympathetic nerve activity, MSNA) were measured with microneurography, testing whether ARBs inhibit central sympathetic outflow.

What Was Measured

The researchers tested this proposition in 19 patients with essential hypertension, evaluating whether the angiotensin receptor blockers (ARBs) eprosartan and losartan had identifiable antiadrenergic properties.

PubMed files the paper under topics including Acrylates, Angiotensin II Type 1 Receptor Blockers, Angiotensin Receptor Antagonists, Antihypertensive Agents, Hypertension, Imidazoles and Losartan.

What This Means in Plain Language

The paper is a randomized, placebo-controlled and crossover study of Losartan in 19 patients.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

The publication is from 2006 (American journal of physiology. Heart and circulatory physiology), a journal based in United States.

More context: all human trials.