Effects of clonidine on plasma catecholamines and neuropeptide Y in hypertensive patients at rest and during stress

What Was Tested

Researchers studied Neuropeptide Y in this randomized controlled trial publication.

The objectives of this study were to determine (a) whether plasma NPY concentrations are altered during different types of stress (cold pressor test, mental stress, and active orthostatism) and (b) whether clonidine, via its central sympatholytic effect, affects the stress-induced blood pressure, NPY, and/or catecholamine changes.

Why It Was Studied

Neuropeptide Y (NPY), a potent vasoconstrictor agent reported to be released, in addition to norepinephrine (NE), by sympathetic nerve endings during stress, may contribute to the pressor response to various stimuli.

The blood pressure and heart rate were recorded during three control periods, each followed by either a cold pressor test (CPT), a mental stress test (MS: mental arithmetic), or active orthostatism (AO), performed in a random order.

Who Took Part

PubMed indexes the participants as adults and middle-aged adults, both men and women.

How the Study Was Run

The researchers set it up as a randomized, double-blind, placebo-controlled and parallel-group study.

The participants were allocated by chance, so the Neuropeptide Y group and the comparison group should start out alike.

Neither the participants nor the staff measuring them knew who was on Neuropeptide Y, so expectations could not easily colour the readings.

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

The Neuropeptide Y group and the comparison group ran side by side rather than switching.

What Was Measured

The blood pressure and heart rate were recorded during three control periods, each followed by either a cold pressor test (CPT), a mental stress test (MS: mental arithmetic), or active orthostatism (AO), performed in a random order.

Venous blood samples for catecholamines and NPY determination were taken at the end of each control and test period.

Topics PubMed links to this paper include Catecholamines, Clonidine, Cold Temperature, Epinephrine, Hypertension, Hypotension, Orthostatic and Neuropeptide Y.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Neuropeptide Y.

The publication is from 1993 (Journal of cardiovascular pharmacology), a journal based in United States.

More context: the Neuropeptide Y compound page, all human trials.