Tritiated Etorphine and Naloxone Binding to Opioid Receptors in Caudate Nucleus in Schizophrenia

1985 ◽  
Vol 146 (5) ◽  
pp. 507-509 ◽  
Author(s):  
F. Owen ◽  
R. C. Bourne ◽  
M. Poulter ◽  
T. J. Crow ◽  
S. J. Paterson ◽  
...  
Keyword(s):  
Caudate Nucleus ◽  
Opioid Receptor ◽  
Opioid Receptors ◽  
Receptor Binding ◽  
Binding Sites ◽  
Specific Binding ◽  
Post Mortem ◽  
Consistent Finding ◽  
Study Offer ◽  
Opioid Receptor Binding

SummaryOpioid receptor binding sites were assessed in membrane preparations of caudate nucleus from post-mortem brains of controls and of patients with schizophrenia. There was no difference between the two groups in the total specific binding of 3H-etorphine or in its ‘μ’ and (‘δ+χ’) components. Similarly, the binding of 3H-naloxone did not differ between patients and controls. It is concluded that a previous report of reduced opioid receptors in caudate of schizophrenics is unlikely to prove a consistent finding and that the results of the present study offer no support to the claim that there is a general disturbance in opiate mechanisms in schizophrenia.

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.

scholarly journals Synthesis and Opioid Receptor Binding Affinities of 2-Substituted and 3-Aminomorphinans: Ligands for μ, κ, and δ Opioid Receptors

2010 ◽  
Vol 53 (1) ◽  
pp. 402-418 ◽  
Author(s):  
Michael Decker ◽  
Yu-Gui Si ◽  
Brian I. Knapp ◽  
Jean M. Bidlack ◽  
John L. Neumeyer
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Receptor Binding ◽  
Binding Affinities ◽  
Opioid Receptor Binding

Ligand recognition in μ opioid receptor: experimentally based modeling of μ opioid receptor binding sites and their testing by ligand docking

1996 ◽  
Vol 4 (12) ◽  
pp. 2151-2166 ◽  
Author(s):  
Takeshi Sagara ◽  
Hiromu Egashira ◽  
Mikako Okamura ◽  
Ikuo Fujii ◽  
Yasuyuki Shimohigashi ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Receptor Binding ◽  
Binding Sites ◽  
Ligand Docking ◽  
Ligand Recognition ◽  
Μ Opioid Receptor ◽  
Opioid Receptor Binding

scholarly journals δ-Opioid receptor binding sites in rodent spinal cord

1990 ◽  
Vol 100 (2) ◽  
pp. 319-323 ◽  
Author(s):  
J.R. Traynor ◽  
J.C Hunter ◽  
R.E. Rodriguez ◽  
R.G. Hill ◽  
J. Hughes
Keyword(s):  
Spinal Cord ◽  
Opioid Receptor ◽  
Receptor Binding ◽  
Binding Sites ◽  
Δ Opioid Receptor ◽  
Opioid Receptor Binding

scholarly journals Kinetic Analysis of Transport and Opioid Receptor Binding of [3H](−)-Cyclofoxy in Rat Brain in vivo: Implications for Human Studies

1991 ◽  
Vol 11 (2) ◽  
pp. 183-203 ◽  
Author(s):  
Yasufumi Sawada ◽  
Ryosei Kawai ◽  
Mary McManaway ◽  
Hideo Otsuki ◽  
Kenner C. Rice ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Receptor Binding ◽  
Specific Binding ◽  
Receptor Site ◽  
Brain Structures ◽  
Tissue Loss ◽  
Opioid Antagonist ◽  
Binding Potential ◽  
Opioid Receptor Binding

[3H]Cyclofoxy (CF: 17-cyclopropylmethyl-3,14-dihydroxy-4,5-α-epoxy-6-β-fluoromorphinan) is an opioid antagonist with affinity to both mu and kappa subtypes that was synthesized for quantitative evaluation of opioid receptor binding in vivo. Two sets of experiments in rats were analyzed. The first involved determining the metabolite-corrected blood concentration and tissue distribution of CF in brain 1 to 60 min after i.v. bolus injection. The second involved measuring brain washout for 15 to 120 s following intracarotid artery injection of CF. A physiologically based model (Sawada et al., 1990 a) and a classical compartmental pharmacokinetic model (Wong et al., 1986 a) were compared. The models included different assumptions for transport across the blood-brain barrier (BBB); estimates of nonspecific tissue binding and specific binding to a single opiate receptor site were found tobe essentially the same with both models. The nonspecific binding equilibrium constant varied modestly in different brain structures ( Keq = 3–9), whereas the binding potential (BP) varied over a much broader range (BP = 0.6–32). In vivo estimates of the opioid receptor dissociation constant were similar for different brain structures ( KD = 2.1–5.2 n M), whereas the apparent receptor density ( Bmax) varied between 1 (cerebellum) and 78 (thalamus) pmol/g of brain. The receptor dissociation rate constants in cerebrum ( k4 = 0.08–0.16 min−1; koff = 0.16–0.23 min−1) and brain vascular permeability ( PS = 1.3–3.4 ml/min/g) are sufficiently high to achieve equilibrium conditions within a reasonable period of time. Graphical analysis (Patlak and Blasberg, 1985) of the data is inappropriate due to the high tissue-loss rate constant ( kb = 0.03–0.07 min−1) for CF in brain. From these findings, CF should be a very useful opioid receptor ligand for the estimation of the receptor binding parameters in human subjects using [18F]CF and positron emission tomography.

Sign in / Sign up

Export Citation Format

Share Document