Opiates endogenous

Leu-enkephalin, Met-enkephalin [59141-40-11 polypeptide multiple tissues endogenous opiates... 

In the anterior pituitary gland (see Hormones, anteriorpituitaryhormones), both adrenocorticotropic hormones (ACTH) and the endogenous opiate hormone, P-endorphin, are synthesized from a common prohormone (2) (see Opioids,endogenous). In the adrenal medulla, five to seven copies of another opiate hormone, methionine—enkephalin (Met-enkephalin), and one copy of leucine—enkephalin (Leu-enkephalin) are synthesized from each precursor molecule (3). 

Enkephalins and Endorphins. Morphine (142), an alkaloid found in opium, was first isolated in the early nineteenth century and widely used in patent medicines of that eta. It is pharmacologically potent and includes analgesic and mood altering effects. Endogenous opiates, the enkephalins, endorphins, and dynotphins were identified in the mid-1970s (3,51) (see Opioids, endogenous). Enkephalins and endorphins ate Hsted in Table 9. 

In the strict sense, opiates are drugs which are derived from opium and include the natural products morphine, codeine, thebaine and many semi-synthetic congeners derived from them. In the wider sense, opiates are morphine-like drugs with non-peptidic structures. The old term opiates is now more and more replaced by the term opioids which applies to any substance, whether endogenous or synthetic, pqrtidic or non-peptidic, that produces morphine-like effects through an action on opioid receptors. 

Similar to endogenous opioids, opiates like morphine and other synthetic opioids activate G-protein-coupled receptors which couple to G-proteins of the Gi/0 family. 

Jones RT Dependence in non-addict humans after a single dose of morphine, in Endogenous and exogenous opiate agonists and antagonists. Edited by Way EL. New York, Pergamon, 1979, pp 557-560... 

Zadina JE, Martiri Schild S, Gerall AA, et al Endomorphins novel endogenous mu-opiate receptor agonists in regions of high mu-opiate receptor density. Ann N Y... 

Review] [67 refs]. Clin Diagn Lab Immunol 7 719-723 Bodnar RJ (2007) Endogenous opiates and behavior 2006. Peptides 28 2435-2513 Boekhoudt GH, Guo Z, Beresford GW, Boss JM (2003) Communication between NF-kappa B and Spl controls histone acetylation within the proximal promoter of the monocyte chemoattractant protein 1 gene. J Immunol 170 4139-4147... 

Zadina JE, Hackler L, Ge LJ, Kastin AJ. A potent and selective endogenous agonist for the mu opiate receptor. Nature (London) 1997 386 499-502. 

When Montgomery and I published our article, we thought we had disproven another theory of placebo effects - the theory that placebo effects are produced by the release of endorphins in the brain. In 1978 researchers at the University of California in San Francisco discovered that when placebos reduce pain, they may stimulate the release of endorphins.18 Endorphins, the existence of which had only been discovered a few years earlier, are opioids that are produced naturally by the brain. Just like the opiates that are derived from opium - morphine and codeine, for example - endorphins reduce the sensation of pain. The University of California researchers reasoned that if placebos can mimic the effects of opiate drugs, maybe they do so by stimulating the release of the brain s endogenous opioids. 

The identification of the morphine receptor spurred an effort in many laboratories to find an endogenous agonist for which that receptor was normally intended. Ultimately, a pair of pentapeptides that bound quite tightly to opiate receptors were isolated from mammalian brains. These peptides, called enkephalins (2, 3), show many of the activities of synthetic opiates in isolated organ systems. They do in fact show analgesic activity when injected directly into the brain. It is thought that lack of activity by other routes of administration is due to their rapid inactivation by peptide cleaving enzymes. 

Endorphins are found primarily in the limbic system, hypothalamus, and brainstem. Enkephalins and dynorphin (in smaller quantities) are found primarily in the periaqueductal gray matter (PAG) of the midbrain, the limbic system, and the hypothalamus. These endogenous substances mimic the effects of morphine and other opiate drugs at many points in the analgesic system, including in the dorsal horns of the spinal cord. 

If opiates are such addictive and potentially lethal compounds, why does the body respond to them As with the cannabinoids (Chapter 7), it has been discovered that the body and brain possess numerous opiate-specific receptor sites. As many as nine receptor subtypes have been identified, with three of them being the most important p (mu), k (kappa) and 8 (delta). The finding that the distribution of opiate receptors did not parallel the distribution of any known neurotransmitter prompted the search for and identification of a number of endogenous compounds specific to these receptors. These enkephalins and endorphins are manufactured within the brain and other body systems (especially the gut and intestines) and form the body s natural response to pain. They appear to be produced in bulk chains of amino acids called polypeptides , with each active neurotransmitter being composed of around five amino acid molecules. These active neurotransmitters are subsequently cleaved from the larger polypeptides at times of demand for example, it has been demonstrated that the plasma levels of these active compounds rise during childbirth, traumatic incidents and vigorous physical exercise. 

Endorphin An endogenous opiate neuropeptide (endogenous morphine). 

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