Multiple opioid receptors

The opioid peptides vary in their binding affinities for the multiple opioid receptor types. Leu- and Met-enkephalin have a higher affinity for 5-receptors than for the other opioid receptor types (68), whereas the dynorphin peptides have a higher affinity for K-sites (69). P-Endorphin binds with equal affinity to both p- and 5-receptors, but binds with lower affinity to K-sites (70). The existence of a P-endorphin-selective receptor, the S-receptor, has been postulated whether this site is actually a separate P-endorphin-selective receptor or is a subtype of a classical opioid receptor is a matter of controversy (71,72). The existence of opioid receptor subtypes in general is quite controversial although there is some evidence for subtypes of p- (73), 5-(74), and K-receptors (72,75), confirmation of which may be obtained by future molecular cloning studies. 

Sharp BM (2003) Opioid receptor expression and intracellular signaling by cells involved in host defense and immunity. Adv Exp Med Biol 521 98-105 Sharp BM (2006) Multiple opioid receptors on immune cells modulate intracellular signaling. Brain Behav Immun 20 9-14... 

Mulder AH and Schoffelmeer ANM (1993). Multiple opioid receptors and presynaptic modulation of neurotransmitter release in the brain. In A Herz (ed.), Opioids. I Handbook of Experimental Pharmacology (Vol. 104, pp. 125-144). Springer-Verlag, New York. 

Opioids produce a large variety of pharmacological responses by interacting with multiple opioid receptors. The indirect evidence for the presence of these multiple receptors is as follows ... 

Li X, Keith DE Jr, Evans CJ. Multiple opioid receptor-like genes are identified in diverse vertebrate phyla. FEBS Lett 1996 397 25-29. 

Shar-p BM (2006) Multiple opioid receptors on immune cells modulate inti acellulai signaling. Brain Behav Immun 20 9—14. 

Opiate effects are mediated via multiple opioid receptors such as the mu, kappa, delta, and sigma. The mu receptors mediate analgesia, euphoria, physical dependence, and depression of ventilation. 

Discovery of Multiple Opioid Receptor Types and Current Nomenclature, 341... 

Eghbali M, Santoro C, Paredes W, Gardner EL, Zukin RS (1987) Visualization of multiple opioid-receptor types in rat striatum after specific mesencephalic lesions. Proc. Nat. Acad. Sci. USA, 84, 6582-6586. 

The identification of multiple opioid receptors has been adequately accomplished with the subsequent discovery of certain selective potential agonists as well as antagonists and the two most sophisticated and reliable assay methods as given below ... 

James IF, Goldstein A. Site-directed alkylation of multiple opioid receptors. I. Binding selectivity. Mol Pharmacol. 1984 25 337-342. 

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