Opioid receptors affecting

Since they are linked to G-proteins, opioid receptors affect intracellular Ca and protein phosphorylation. Another principal biochemical effect of opiates is the inhibition of adenylate cyclase (AC), which decreases cAMP production. 

The pharmacological and/or adverse effects of a drug can be reversed by co-administration of drugs which compete for the same receptor. For example, an opioid receptor antagonist naloxone is used to reverse the effects of opiates. Drugs acting at the same site with opposite effects also can affect each other, e.g. the reduction in the anticoagulant effect of warfarin by vitamin K. 

Classification of the narcotic analgesics is based on their activity at the opioid receptor sites. Although five categories of opioid receptors have been identified, only three of these receptors affect the action of the narcotic... 

GUal precursors in the ventricular and subventricular zones can also express opioid receptors (Zhu et al. 1998 Reznikov et al. 1999 Stiene-Martin et al. 2001 Kim et al. 2006 Tripathi et al. 2008). Immature glia and adult progenitors express opioid receptors, which affect ceUular maturation (Stiene-Martin and Hauser 1990, 1991 Stiene-Martin et al. 1991 Persson et al. 2003,2006) and cell fate decisions (Kim et al. 2006). Importantly, gUal precursors (Khurdayan et al. 2004 Lawrence et al. 2004 Buch et al. 2007), and espedaUy immature oUgodendroglia (Khurdayan et al. 2004 Hauser et al. 2008), also appear to be vulnerable to opioids and HIV-1 proteins. 

Casein refers to a family of proteins, namely, ttgi-, 0. 2-, p-, and k-caseins (Table 5.1). Digestion of a- and p-caseins leads to production of peptides that may bind to opioid receptors that exist in the nervous, endocrine, immime, or gastrointestinal system (Kampa et ah, 1996 Meisel, 2004). These compoimds may modulate absorption processes in the gut and can potentially affect gastrointestinal fimction through transit... 

Zubieta JK et al Regional mu opioid receptor regulation of sensory and affective dimensions of pain. Science 2001 293 311. [PMID 11452128]... 

In vivo studies employing tests of acute pain unequivocally showed the involvement of Katp, Kv1.1 and Ca2+-activated K+ channels in supraspinal, spinal and peripheral analgesia produced by different classes of analgesics. Furthermore, two-pore-domain and G-protein gated inward rectifier (Kir3.x) K+ channels are affected by volatile anesthetics. The latter also contribute to p- and K-opioid receptor-mediated analgesia (Ikeda et al., 2000). 

Opioid analgesics such as oxycodone act directly on the central nervous system by stimulating opioid receptors in the brain. This action affects how the pain is perceived and can alter the user s emotional response to the pain. 

Neurotransmission events involved in the sensation of reward are also important. Alcohol affects local concentrations of serotonin, opioids, and dopamine—neurotransmitters involved in brain reward circuits. Alcohol also has complex effects on the expression of receptors for these neurotransmitters and their signaling pathways. The discovery that naltrexone, a nonselective opioid receptor antagonist, helps patients who are recovering from alcoholism abstain from drinking supports the idea that the neurochemical reward system is shared by drugs associated with physical and psychological dependence. 

Hollt, V. A polymorphism (A118G) in the mu-opioid receptor gene affects the response to morphine-6-glucuronide in humans. Pharmacogenetics 2002,12 1-2. 

Gelernter J, Kranzler HR. Variant detection at the delta opioid receptor (OPRD1) locus and population genetics of a novel variant affecting protein sequence. Hum Genet 2000 107 86-88. 

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