Alpha-neoendorphin

Where it comes from

Made in

Hypothalamus, striatum and pituitary, with the dynorphins

Sent out by

With the dynorphins

Acts on

• Kappa receptors

What it does

• A potent opiate agonist, as all the prodynorphin peptides are, and the first of them to be isolated ¹
• Cut from prodynorphin ahead of dynorphin A, so a tissue rich in it is using a different set of processing enzymes ³
• Trimmed by one residue to beta-neoendorphin, which is a little weaker ²

In medicine

• No medicine copies it, and it is not measured outside research laboratories
• The approved kappa agonists act at its receptor, so a reader looking for a medicine will find it under dynorphin A rather than here

Beyond the body’s own use

• Nothing containing it is in trials, and no analogue of it has been given to a person
• Telling it from beta-neoendorphin takes chromatography, or an antiserum raised against the single extra lysine at its end: the two differ by that one residue, which is why most studies report them together ²
• What is unknown is whether the front and back halves of prodynorphin are ever released separately. Nothing is known to switch one cut on and the other off, so the neoendorphins and the dynorphins are usually treated as one output ³