Effect of lipids on binding characteristics of opiod receptors

Apaydın, Serpil
Effect of lipids on binding characteristics of opioid receptors in membranes prepared from rat brain were studied. Lipid concentrations causing changes in specific binding of [3H]Endomorphin-1 (ProE1), an opioid agonist highly specific to mu-type opioid, [3H]Ile5,6deltorphin II (DIDI), an agonist ligand highly specific to delta type receptor and [3H]Naloxone (Nlx), a universal opioid receptor antagonist were determined. Inhibition of [3H]ProE1, [3H]DIDI and [3H]Nlx specific binding was also examined by homologous displacement experiments in the presence and absence of lipids. In order to understand whether the changes occurring in the specific binding is due to changes in equilibrium dissociation constant (KD) or maximum number of binding sites (Bmax), the equilibrium binding experiments were performed. Arachidonic acid (AA) inhibited binding of both agonist and antagonist ligand in a dose dependent manner with IC50 values of 0.15, 0.1, and 0.6 mM for [3H]ProE1, [3H]DIDI and [3H]Nlx, respectively. Kd values were not affected while Bmax values decreased 38 % and 76 % for mu, and delta receptor subtypes, respectively. For [3H]Nlx, Bmax values decreased 20 and 56 % in the absence and presence of 100 mM NaCl, respectively. Cholesteryl hemisuccinate (CHS) enhances (100 % of control) ligand binding at mu-sites however no effect was encountered at delta sites. Furthermore, CHS also enhances (50 % of control) the binding of antagonist ligand in the absence of NaCl. Bmax values were increased by 70 % for mu sites and 40% for antagonist ligand binding site. Under similar conditions Kd values were not affected. Phosphatidic acid (PA) and phosphatidylcholine (PC) exhibited negligible effect on ligand binding. PA decreased specific binding of ProE1 and DIDI by 16 and 10 %, respectively. Specific binding of antagonist ligand Nlx decreased 11 % in the presence of NaCl whereas in the


Effect of arachidonic acid on specific binding of [H-3]naloxone to opioid receptors
Apaydin, S; Öktem, Hüseyin Avni (2000-01-01)
The effects of arachidonic acid (AA) on binding of [H-3]naloxone to the agonist and antagonist configurations of opioid receptors were investigated in rat brain. Equilibrium binding parameters of the agonist and antagonist configurations of the receptors were evaluated from homologue displacement data in the presence or absence of AA. Addition of AA at a concentration of 0.6 mM (1.5 mu mole/mg of protein) reduced by 22% and 53% the maximal number of binding sites (B-max) respectively in the absence or prese...
Effects of Isoflurane, Halothane, and Chloroform on the Interactions and Lateral Organization of Lipids in the Liquid-Ordered Phase
Türkyılmaz, Serhan; Regen, Steven L. (2011-12-06)
The first quantitative insight has been obtained into the effects that volatile anesthetics have on the interactions and lateral organization of lipids in model membranes that mimic "lipid rafts". Specifically, nearest-neighbor recogntion measurements, in combination with Monte Carlo simulations, have been used to investigate the action of isoflurane, halothane, and chloroform on the compactness and lateral organization of cholesterol-rich bilayers of 1,2-dipalmitoylsn-glycero-3-phosphocholine (DPPC) in the...
Effect of protein aggregation in the aqueous phase on the binding of membrane proteins to membranes
Doebler, R; Basaran, N; Goldston, H; Holloway, PW (Elsevier BV, 1999-02-01)
Analysis of the binding of hydrophobic peptides or proteins to membranes generally assumes that the solute is monomeric in both the aqueous phase and the membrane. Simulations were performed to examine the effect of solute self-association in the aqueous phase on the binding of monomeric solute to lipid vesicles. Aggregation lowered the initial concentration of monomeric solute, which was then maintained at a relatively constant value at the expense of the aggregated solute, as the lipid concentration was i...
Effect of fabrication and process parameters on the morphology and performance of a PAN-based zeolite-filled pervaporation membrane
Okumus, E; Gurkan, T; Yılmaz, Levent (Elsevier BV, 2003-09-15)
The aim of this study is to develop a novel pervaporation membrane for dehydration of azeotropic ethanol-water mixture and to investigate the effect of membrane preparation and process parameters on the membrane performance. Zeolites (3A, 4A and 13X) are added as fillers to the base polymer poly [acrylonitrile] (PAN). It is observed that the volatility of the casting solvent and the annealing temperature strongly affect the performance and morphology of the manufactured membranes. Scanning electron microgra...
Effect of suppressive DNA on CpG-induced immune activation.
Yamada, H; Gursel, I; Takeshita, F; Conover, J; Ishii, KJ; Gürsel, Mayda; Takeshita, S; Klinman, DM (The American Association of Immunologists, 2002-11-15)
Bacterial DNA and synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG motifs stimulate a strong innate immune response. This stimulation can be abrogated by either removing the CpG DNA or adding inhibitory/suppressive motifs. Suppression is dominant over stimulation and is specific for CpG-induced immune responses (having no effect on LPS- or Con A-induced activation). Individual cells noncompetitively internalize both stimulatory and suppressive ODN. Studies using ODN composed of both stimula...
Citation Formats
S. Apaydın, “Effect of lipids on binding characteristics of opiod receptors,” Ph.D. - Doctoral Program, Middle East Technical University, 2005.