5-Opioid receptors affinity

Table 1 Opioid Receptor Affinities of Cyclic Dermorphin Analogues ... 

Table 2 Antagonist Potencies and Opioid Receptor Affinities of TIPP Analogues... 

Table 3.5. OPIOID RECEPTOR AFFINITIES OF BENZOFUROPYRIDINE DERIVATIVES [92]...

Naloxone has a short duration of action and repeated administration may be necessary to successfully counteract the effect of longer-acting opioids. The degree of respiratory depression corresponds to opioid receptor affinity and highly potent opioids induce severe respiratory... 

Jacobs, A.M. and Youngblood, F. Opioid receptor affinity for agonist-antagonist analgesics, J. Am. Paediatr. Med. Assoc. 1992, 82, 520-524. 

Opioid receptor binding Ethylmorphine is an ethyl congener of codeine and has a low opioid receptor affinity (Chen et al., 1991). Like codeine, it is metabolized to the active principle morphine. 

Opioid receptor affinity Ketobemidone is a p-selective synthetic opioid with a receptor affinity similar to morphine (Christensen, 1993). 

Opioid receptor binding Levomethadone is the more potent and p-selective levo-enantiomer of racemic methadone (Sim, 1973). It has an opioid receptor affinity in the range of morphine. 

Opioid receptor affinity Tramadol (Frink et al., 1996) itself has a weak opioid receptor affinity, the active metabolite O-desmethyl-tramadol has p-selectivity and p-affinity about 10 times lower than that of morphine. 

Table 2 Opioid receptor affinities of J-113397 and related compounds.

Table 4 Opioid receptor affinities of selected ORL-1 ligands.

Tramadol, however, is thousands of times less potent than morphine as an analgesic agent [18]. It is marketed in the racemic form, and each enantiomer has distinct pharmacological actions. The (+)-isomer is a weak MOP agonist, while the (-)-isomer inhibits neurotransmitter reuptake (norepinephrine and serotonin). The O-demethylated metabolite has improved opioid receptor affinity but is still much less potent (35-fold) than morphine. The ability for this metabolite to ameliorate the analgesic effects of tramadol has not been well studied and remains questionable. The drug has been used for decades in Europe, but was only recently introduced in the United States. It has a greater safety profile than morphine, and produces no respiratory depression or constipation. It is also claimed to be nonaddictive, but remains unscheduled. 

Another universal antagonist is the naltrexone-derived nalmefene (14). This 6-methylene derivative of naltrexone shows higher k opioid receptor affinity [51, 52], Nalmefene is a potent, orally active opioid antagonist with a... 

Opioid receptor affinity labels have been reported for other narcotic analgesics, for example, piperidines, 293 294 benzomorphans, 295 296 and mor-phinans, 297,298 and the topic is further discussed in Chapter 13 (p. 445). Not only is the oxo-function in the 4,5-epoxymorphinan C-ring available for ready elaboration, but C-6 substituents, although they affect agonist potency, do not impair unduly receptor affinity. 299 301 ... 

Liebmann C, Schrader U, Brand V (1989) Opioid receptor affinities of the blood-derived tetrapeptides hemorphin and cytochrophin. Eur J Pharmacol 166 523-526 Lin S, Boey D, Herzog H (2004) NPY and Y receptors lessons from transgenic and knockout models. Neuropeptides 38 189-200... 

Schultz, A. G., Wang, A., Alva, C., Sebastian, A., Glick, S., Deecher, D. C., Bidlack, J. M. Asymmetric Syntheses, Opioid Receptor Affinities, and Antinociceptive Effects of 8-Amino-5,9-methanobenzocyclooctenes, a New Class of Structural Analogs of the Morphine Alkaloids. J. Med. Chem. 1996, 39, 1956-1966. 

Prior to cloning of the opioid receptors, affinity for these receptors was most commonly determined by the use of homogenates or membrane fractions from rat, guinea pig, or mouse brain, which contain all three types of opioid receptors. The relative amounts of different opioid receptor types vary between species, however, particularly for k receptors. In rat brain k opioid receptors constitute only about 10-15% of the total number of opioid receptor sites (124), whereas in species such as guinea pig they represent approximately 30% of the total opioid receptor population (125). Over 80% of the opioid receptors in the guinea pig cerebellum are k receptors (126), so this tissue was frequently used in K-receptor bind-... 

Table 7.8 Opioid Receptor Affinities and Opioid Activity in the GPI and MVD of a Variety of Opioid Ligands CommonfyUsed to Study Opioid Receptors ...

Table 7.11 Opioid Receptor Affinities, k Selectivity, and Analgesic Activity of k Opioid Ligands ...

Table 7.12 Opioid Receptor Affinities, 6 Selectivity, and Opioid Activity in the MVD of 6 Opioid Agonists ...

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