Endothelin-1 and cerebral blood flow: influence of hypoxia, hypercapnia and indomethacin on circulating endothelin levels in healthy volunteers

What Was Tested

The paper reports a study of Endothelin-1, published as a randomized controlled trial.

In protocol A, 23 subjects were exposed to moderate hypoxia.

Two different FiO2 were chosen, light hypoxia in protocol B was chosen due to application of a known cerebral vasoconstrictor with unknown effect on cerebral autoregulation.

Who Took Part

According to the abstract, 23 subjects were involved.

PubMed indexes the participants as teenagers and adults, both men and women.

In protocol B, 29 subjects were randomized to one of four groups: (1) placebo, (2) indomethacin, (3) indomethacin+light hypoxia and (4) indomethacin+hypercapnia.

How the Study Was Run

In design terms this was a randomized, double-blind and placebo-controlled study.

Because people in this Endothelin-1 study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

As a double-blind Endothelin-1 study, the assignments were hidden from both participants and investigators until the end.

The comparison arm used a placebo, so changes seen with Endothelin-1 could be set against what happens without it.

What Was Measured

The subject headings attached to it are Cerebrovascular Circulation, Endothelins, Hypercapnia, Hypoxia, Indomethacin and Radioimmunoassay.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Endothelin-1 in 23 subjects.

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 1994 (Scandinavian journal of clinical and laboratory investigation), a journal based in England.

More context: the Endothelin-1 compound page, all human trials.