The action of a synthetic derivative of Met5-enkephalin-Arg6-Phe7 on behavioral and endocrine responses

- The neuroendocrine actions of a synthetic derivate of MERF were investigated.
- We examined the effect on corticosterone secretion and open field behavior.
- Tyr-d-Ala-Gly-Phe-d-Nle-Arg-Phe (DADN) activated the HPA axis and stimulated the horizontal and vertical locomotion in the open field experiment.
- Predominantly μ-receptors mediate the endocrine and behavioral actions of DADN.