Peptides, endogenous opiate

Endogenous opiate peptides Naloxone precipitates nicotine withdrawal thresholds... 

Birdsall, N.J.M., Hulme, E.C., Bradbury, A.F., Smyth, O.G. and Snell, C.R., Opiates and Endogenous Opioid Peptides, 1976, Elsevier/North-Holland Biomedical Press, Amsterdam, p. 19. 

The demonstration of the existence of strictly defined SARs. which is perhaps Ihe most important criterion of drug action at a specific receptor site, has made possible the most important pharmacologic discoveries. For example, the analgesic actions of morphine and related agents, which are indicative of specific receptors, led to die discovery of endogenous opiate peptides, i.e., the leucine and methionine enkephalins and endorphins. 

Dynorphin AJ (peptide) Endogenous animal opiate kO-R agonist [analgesic, endogenous anti-convulsant]... 

G H Loew and D S Berkowitz, in Opiates and Endogenous Opioid Peptides, p 399, Elsevier, Amsterdam (1976)... 

Yang J (1994) Intrathecal administration of oxytocin-induced analgesia in low-back-pain involving the endogenous opiate peptide system. Spine 19 867-871... 

Because ACTH synthesis originates from the POMC precursor peptide, its production by the pituitary is closely tied to the secretion of endogenous opiate peptides, such as P-endorphin. The physiological effects of endogenous opiates include (1) sedation, (2) an increased threshold of pain, and (3) autonomic regulation of respiration, blood pressure, and heart rate. These peptides are also involved in modifying endocrine responses to stress and water balance... 

If opiates and opiate peptides are acting on Ca + disposition they are not unique in this respect. Neurotransmitter release is known to be a Ca -dependent process, and, in fact a number of neurotransmitters or pharmacologic agents tors such as norepinephrine, adenosine and oxotremorine have been reported to act by inhibition of Ca + influx (123,125,126). This must mean that opiates produce their characteristic spectrum of effects, not because they have a unique mode of neuromodula-tory action, but because the receptors for the endogenous opiate ligands are located stratgetically at selective neuronal sites for the mediation of their specific effects. 

Opiates and endogenous opioid peptides, Ed. H.W. Kosterlitz, Amsterdam Elsevier/North Holland Biomed. Press, 1976, pp. 361-368. 

Endogenous opiate peptides represented by endorphins, enkephalins, and dynorphins Three receptor families p, K, and 5... 

In addition to the endogenous opiate peptides, several other peptides function as neurotransmitters (e.g., substance P, vasoactive intestinal peptide). These agents are generally cleaved from larger peptide precursors. They can assume a variety of three dimensional shapes, making it difficult to assess the chemistry of peptide-receptor interactions. For this reason, no chemical agonists (other than morphine) or antagonists have been identified for peptide receptors. 

Smith, T. W., Hughes, J., Kosterlitz, H. W., and Sosa, R. P. (1976). In Opiates and Endogenous Opioid Peptides, pp. 57-62. Elsevier/North-Holland Press, Amsterdam. 

Garcin F. and Coyle J. T. (1976) Ontogenetic development of ( H)naloxone binding sites and endogenous morphme-like factors in rat brain, in Opiates and Endogenous Opioid Peptides (Kostehtz, H. W., ed.) pp. 41-48. Elsevier/North Holland, Amsterdam... 

The cause of PMS is complex and not well understood. Some theories propose progesterone deficiency, endogenous opiate peptide excess, or... 

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. 

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