They called this molecule "enkephalin"(meaning "in the head"). It had some of the qualities of morphine, which helped answer the question of why the brain had receptors for morphine. Hughes ...
Enkephalin, ein aus zwei Pentapeptiden bestehendes Gemisch endogener Peptide mit morphinähnlichen Wirkungen (Opioidpeptide). Methionin-E. (Met-E.), H-Tyr-Gly-Gly-Phe-Met-OH, und Leucin-E. (Leu-E.) ...
μ (μ1, μ2) β-Endorphin, Met-Enkephalin Morphin, Methadon, Pethidin, Fentanyl, Buprenorphin Naloxon, Naltrexon, Pentazocin, Nalbuphin Hemmung der Noradrenalin ...