Cutaneous nociception and neurogenic inflammation evoked by PACAP38 and VIP

What Was Tested

Researchers studied VIP (Vasoactive Intestinal Peptide) and PACAP in this randomized controlled trial publication.

Pituitary adenylate cyclase-activating peptide-38 (PACAP38) and vasoactive intestinal peptide (VIP) belong to the same secretin-glucagon superfamily and are present in nerve fibers in dura and skin.

Using a model of acute cutaneous pain the researchers explored differences in pain perception and vasomotor responses between PACAP38 and VIP in 16 healthy volunteers in a double-blind, placebo-controlled, crossover study.

Who Took Part

The abstract describes 16 volunteers taking part.

By PubMed's age tags, the people studied were young adults, adults and middle-aged adults, both men and women.

How the Study Was Run

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

Because people in this VIP (Vasoactive Intestinal Peptide) study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Blinding on both sides kept the volunteers and researchers unaware of who received VIP (Vasoactive Intestinal Peptide).

A placebo (an inactive look-alike) gave the VIP (Vasoactive Intestinal Peptide) group a baseline to be compared against.

Each person switched between VIP (Vasoactive Intestinal Peptide) and the comparison at some point, usually with a gap in between.

What Was Measured

Pituitary adenylate cyclase-activating peptide-38 (PACAP38) and vasoactive intestinal peptide (VIP) belong to the same secretin-glucagon superfamily and are present in nerve fibers in dura and skin.

Measurements included pain intensity on a visual analog scale (VAS), blood flow by laser Doppler flowmetry, visual flare and wheal.

The subject headings attached to it are Acute Disease, Administration, Cutaneous, Models, Neurological, Neurogenic Inflammation, Nociceptors, Pain and Pituitary Adenylate Cyclase-Activating Polypeptide.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of VIP (Vasoactive Intestinal Peptide) and PACAP in 16 volunteers.

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 2010 (The journal of headache and pain), a journal based in England.

More context: the VIP (Vasoactive Intestinal Peptide) compound page and the PACAP compound page, all human trials.