Opioid Receptors: Cellular and Molecular Mechanisms Underlying Opioid Receptor Function

2012 ◽  
pp. 1304-1312
Author(s):  
Lisa Stowers ◽  
Sandeepa Dey ◽  
Vladana Vukojević ◽  
Yu Ming ◽  
Lars Terenius
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Molecular Mechanisms ◽  
Receptor Function

Direct evidence for the up-regulation of spinal u-opioid receptor function after repeated stimulation of kappa-opioid receptors in the mouse

2003 ◽  
Vol 18 (9) ◽  
pp. 2498-2504 ◽  
Author(s):  
Minoru Narita ◽  
Junaidi Khotib ◽  
Hirokazu Mizoguchi ◽  
Masami Suzuki ◽  
Satoru Ozaki ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Direct Evidence ◽  
Receptor Function ◽  
Kappa Opioid Receptors ◽  
Kappa Opioid ◽  
Repeated Stimulation ◽  
Stimulation Of

scholarly journals Molecular Mechanisms of Opioid Receptor-dependent Signaling and Behavior

2011 ◽  
Vol 115 (6) ◽  
pp. 1363-1381 ◽  
Author(s):  
Ream Al-Hasani ◽  
Michael R. Bruchas
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Molecular Mechanisms ◽  
Human Genetics ◽  
Receptor Subtypes ◽  
Receptor Signaling ◽  
Molecular Pharmacology ◽  
And Behavior ◽  
G Protein Coupled

Opioid receptors have been targeted for the treatment of pain and related disorders for thousands of years and remain the most widely used analgesics in the clinic. Mu (μ), kappa (κ), and delta (δ) opioid receptors represent the originally classified receptor subtypes, with opioid receptor like-1 (ORL1) being the least characterized. All four receptors are G-protein coupled and activate inhibitory G proteins. These receptors form homo- and heterodimeric complexes and signal to kinase cascades and scaffold a variety of proteins.The authors discuss classic mechanisms and developments in understanding opioid tolerance and opioid receptor signaling and highlight advances in opioid molecular pharmacology, behavioral pharmacology, and human genetics. The authors put into context how opioid receptor signaling leads to the modulation of behavior with the potential for therapeutic intervention. Finally, the authors conclude there is a continued need for more translational work on opioid receptors in vivo.

The K+-evoked release of [3H]acetylcholine from slices of rat globus pallidus: modulation by δ-opioid receptors

1991 ◽  
Vol 69 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Bianca B. Ruzicka ◽  
Khem Jhamandas
Keyword(s):  
Globus Pallidus ◽  
Opioid Receptor ◽  
Opioid Receptors ◽  
Cholinergic Neurons ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Release Of Acetylcholine ◽  
Δ Opioid Receptor ◽  
Tritium Release

Previous investigations have shown that the activation of δ-opioid receptors depresses the release of acetylcholine (ACh) in the rat caudate putamen. This finding raised the possibility that the release of ACh is similarly modulated in the globus pallidus, a region containing a distinct population of cholinergic neurons and enriched in enkephalinergic nerve terminals. In the present study the pallidal release of ACh was characterized and the effects of δ-opioid receptor activation on this release were examined. The results show that this release is stimulated by high K+ in a concentration- and Ca2+-dependent manner. D-Pen2,L-Pen5-enkephalin (0.1 – 10 μM), a selective δ-opioid receptor agonist, produced a dose-related inhibition of the 25 mM K+-evoked tritium release. The maximal inhibitory effect, representing a 34% decrease in the K+-induced tritium release, was observed at a concentration of 1 μM. This opioid effect was attenuated by the selective δ-opioid receptor antagonist, ICI 174864 (1 μM). These findings support the role of a δ-opioid receptor in the modulation of ACh release in the rat globus pallidus.Key words: globus pallidus, acetylcholine, enkephalin, release.

scholarly journals Sensitivity to μ-opioid receptor-mediated anti-nociception is determined by cross-regulation between μ- and δ-opioid receptors at supraspinal level

2012 ◽  
Vol 166 (1) ◽  
pp. 309-326 ◽  
Author(s):  
JJ Ballesta ◽  
J Cremades ◽  
M Rodríguez-Muñoz ◽  
J Garzón ◽  
CC Faura
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Μ Opioid Receptor

Fluorescent opioid receptor ligands as tools to study opioid receptor function

2021 ◽  
pp. 107132
Author(s):  
Despina Giakomidi ◽  
Mark F. Bird ◽  
Remo Guerrini ◽  
Girolamo Calo ◽  
David G. Lambert
Keyword(s):  
Opioid Receptor ◽  
Receptor Function ◽  
Receptor Ligands ◽  
Opioid Receptor Ligands

kappa-Opioid antagonist improves cellular bioenergetics and recovery after traumatic brain injury

1991 ◽  
Vol 261 (6) ◽  
pp. R1527-R1532 ◽  
Author(s):  
R. Vink ◽  
P. S. Portoghese ◽  
A. I. Faden
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Receptor Antagonist ◽  
Opioid Receptor ◽  
Opioid Receptors ◽  
Neurological Outcome ◽  
Kappa Opioid Receptors ◽  
Kappa Opioid ◽  
Opioid Receptor Antagonist ◽  
Cellular Bioenergetics

Treatment with opioid receptor antagonists improves outcome after experimental brain trauma, although the mechanisms underlying the protective actions of these compounds remain speculative. We have proposed that endogenous opioids contribute to the pathophysiology of traumatic brain injury through actions at kappa-opioid receptors, possibly by affecting cellular bioenergetic state. In the present study, the effects of the kappa-selective opioid-receptor antagonist nor-binaltorphimine (nor-BNI) were examined after fluid percussion brain injury in rats. Metabolic changes were evaluated by 31P magnetic resonance spectroscopy; the same animals were subsequently followed over 2 wk to evaluate neurological recovery. Nor-BNI, administered intravenously as a 10 or 20 mg/kg bolus at 30 min after injury, significantly improved neurological outcome at 2 wk posttrauma compared with controls. Animals treated with nor-BNI showed significantly greater recovery of intracellular free magnesium concentrations and cytosolic phosphorylation potentials during the first 4 h after injury compared with saline-treated controls. The improvement in cytosolic phosphorylation potential was significantly correlated to neurological outcome. These data support the hypothesis that kappa-opioid receptors mediate pathophysiological changes after traumatic brain injury and that the beneficial effects of opioid-receptor antagonist may result from improvement of posttraumatic cellular bioenergetics.

Opioid receptors in the accessory optic system of the rat: Effects of monocular enucleation

1990 ◽  
Vol 5 (5) ◽  
pp. 497-506 ◽  
Author(s):  
R.A. Giolli ◽  
R.H.I. Blanks ◽  
Y. Torigoe ◽  
R.J. Clarke ◽  
J.H. Fallon ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Receptor Binding ◽  
Mu Opioid Receptor ◽  
Mu Opioid Receptors ◽  
Mu Opioid ◽  
Mu Receptor ◽  
Monocular Enucleation ◽  
Mu Receptors ◽  
Opioid Receptor Binding

AbstractThe presence and concentrations of each of the three subtypes of opioid receptors (mu, kappa, and delta) has been studied in the accessory optic nuclei (dorsal, lateral, and medial terminal nuclei and the interstitial nucleus of the superior fasciculus, posterior fibers: DTN, LTN, MTN, and inSFp) in normal young rats with radioligands directed towards each opioid receptor subtype. The changes in mu opioid receptors have also been investigated in monocularly enucleated rats in which one eye was removed and the rats sacrificed at postoperative day (PO) 2, 3, 5, 7, 14, and 30. As the MTN is the only accessory optic nucleus of the rat large enough for semiquantitative evaluation, the mu receptor population of the MTN has been subjected to optical microdensitometric analysis.All four of the accessory optic nuclei (AOS nuclei) are found to contain exceedingly high levels of mu opioid receptor binding with the selective radioligand [3H]-[D-Ala, MePhe4, Gly-ol5] (DAGO), low levels of kappa opioid receptor binding using the radioligand [3H]-[ethylketocyclazocine] (EKC) together with the competing agents [D-Pro4]-morphiceptin and [D-Ser2, Thr6]-Leu-enkephalin, and an absence of delta opioid receptor binding with the radioligand [3H]-[D-A1a2, D-Leu5]-enkephalin (DADLE) combined with the competing agent [D-Pro4]-morphiceptin. Monocular enucleation, as studied on the mu opioid receptor population with this experimental approach, results in virtually a complete loss of mu opioid receptors throughout all four of the contralaterally located AOS nuclei, including both dorsal and ventral subdivisions of the medial terminal nucleus (MTNd, v). Kappa and delta receptors are very few (kappa receptors) or are lacking (delta receptors) in the AOS nuclei, and for this reason, the effects of monocular enucleation on these two opioid receptor subtypes have not been investigated. Monocular enucleation also produces a significant lowering in mu receptor binding in other primary optic nuclei (the lateral geniculate nuclei, nucleus of the optic tract, and superficial layers of the superior colliculus) and in the pars principalis of the medial geniculate nucleus (description of changes in mu receptors in non-accessory optic primary optic nuclei will be considered elsewhere).Microdensitometric study of the MTNd, v shows that the decreased binding of mu receptors in this nucleus is barely detectable (about 6%) at PO2 and rises to 6–15% at PO3. At PO5 receptor loss reaches approximately 62%, whereas at PO7 it is about 81% complete. At PO14 and PO30, the mu receptor loss is nearly complete at around 93%. Mu receptor loss involves all of the AOS nuclei contralateral, but none ipsilateral, to ocular enucleation, an observation entirely consistent with the overwhelmingly crossed (about 97%) nature of the retinofugal projection to the rat accessory optic nuclei. These opioid receptors represent a prominent feature in the AOS and other primary optic nuclei of the rat. Their role in visuomotor control remains uncertain but probably involves the fine-tuning of information concerned with compensatory eye movements.

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