Neuropeptides in research: Selank, Semax and signalling routes in the brain

What neuropeptides are

Neuropeptides are short protein chains that nerve cells use to talk to each other. They act as messengers, alongside the better known neurotransmitters. Many derive from larger natural proteins.

Researchers study them because they give finely tuned signals. A small peptide can touch a specific route without flooding the whole system.

The Russian research line

Selank and Semax come from research at Russian institutes. Both derive from natural substances in the body. Semax stems from a fragment of the hormone ACTH. Selank is based on tuftsin, a peptide from the immune system.

The researchers wanted molecules more stable than the natural original that stayed measurable longer.

Semax up close

Semax is a chain of seven amino acids. Studies focus on learning behaviour and stress responses in animal models, as a measurable readout of signalling routes. A recurring measurement point is the activity of certain signalling substances in the brain.

Selank and the GABA system

Selank is studied mainly in rodent behavioural models, with anxiety-like behaviour as a readout. Researchers link it to the GABA system, a route that dampens nerve activity.

The measurements concern the behaviour of test animals and substances in brain tissue, not use in people.

BDNF as a recurring theme

BDNF returns in much of this research. It is a protein that helps nerve cells grow and maintain connections. Studies measure whether neuropeptides change BDNF levels in models.

• Learning tasks: behaviour of test animals in standardised learning tests.
• Stress models: behaviour under load.
• Signalling substances: measurements of neurotransmitters and BDNF.

Limits of the research

Much of the evidence comes from animal models and from a research setting published mainly in Russian. Independent, large-scale studies in people are limited. That is why this belongs as a research subject.