PHARMACOLOGICAL STUDY OF AN IRREVERSIBLE PARTIAL AGONIST OF OPIATE RECEPTORS, A-α-CAO

A-α-CAO induces weak analgesia with very short duration in mice and is able to antagonize the analgesic effect of morphine (Mor) up to 3—4 days after a single injection. No tendency of dependence has been observed. It acts as a partial agonist on MVD with Ke value of 9×10~(-9) mol/L. Its antagonist effect remains after several washes and its agonist effect cannot be reversed by naloxone (Nx), provided the incubation time or the concentration of the agent is sufficient. On isolated GPI, A-α-CAO is a pure agonist with IC_(50) of 5.7×10~(-10) mol/L; this agonist effect cannot be removed by washing but can be reversed by Nx. On RVD and RbVD, it has antagonist effect against β-endorphine (β-end) and US0488H, which cannot be washed out easily, and the pA_2are 7.5 and 7.6 respectively. A-α-CAO also inhibits the specific binding of ~3H-etorphine (~3H-Etor) to the P_2 fraction of the mouse brain membrane with an IC_(30) of 3.2×10~(-9) mol/L. The inhibition on the high affinity binding sites of ~3H-Etor     

THE CHOICE OF OPIOID RECEPTOR SUBTYPE IN ISOLATED PREPARATIONS BY OHMEFENTANYL

Ohmefentanyl has significant inhibitory actions on the electrically evoked contractions of guinea pigileum and mouse vas deferens. Their IC_(50) values are 0.15 nM and 0.89 nM, respectively. In the guinea pigileum and the mouse vas deferens, both μ-antagonist naloxone and (μ+κ)-antagonist Mr. 2266 antagonizereadily the agonist action of ohmefentanyl, indicating that ohmefentanyl acts on μ-receptors in the guineapig ileum and the mouse vas deferens. Like other μ-agonists, ohmefentanyl has agonist activity but noantagonist action in the rat vas deferens. In the rabbit vas deferens, the activity of ohmefentanyl is veryweak. The IC_(50) value is 149 nM. These results further indicate that ohmefentanyl is a potent and selectiveμ-agonist.     

ROLE OF CALCIUM IN ELECTRO-ACUPUNCTURE ANALGESIA AND THE DEVELOPMENTS OF ANALGESIC TOLERANCE TO ELECTROACUPUNTURE AND MORPHINE

Role of brain Ca~(2+) in electro-acupuncture analgesia and the development of analgesic tolerance to electro-acupuncture and morphine were studied. At the same time, the inhibition by protein synthesis inhibiturs of the development of analgesic tolerance to electro-acupuncture was observed. The results showed that like morphine tolerance, the brain Ca~(2+) and cAMP levels in mice were enhanced with the development of analgesic tolerance to electro-acupuncture. After treatment with protein synthesis inhibitors anisomycin, actinomycin or cycloheximide the development of analgesic tolerance to electro-acupuncture was inhibited, and concurrently, the brain Ca~(2+) and cAMP levels in the animals greatly reduced. From the changes of brain Ca~(2+) and cAMP levels, the analgesic effects by electro-acupuncture, morphine and lanthanides seem to be very similar and share a mutual ion basis and the mechanism of action. So does the development of analgesic tolerance to electro-acupuncture and morphine. These finding     

Synthesis of Glutamic Acid-based Cluster Galactosides and Their Binding Affinities with Liver Cells

Structurally well defined di-, tri- and tetra-valent cluster galactosides were synthesized in a convenient way.Oligo-glutamic acids were assembled as scaffolds. The presence of amine groups in these three ligands is expected to couple with drugs or genes for delivery. The binding affinities of these cluster galactoses to liver cells were determined by in vitro binding studies. Among them, the tetravalent cluster galactose (19) showed the highest affinity to liver cell. It is therefore a promising targeting device for the specific delivery of drugs or genes to parenchymal liver cells.     

Synthesis of 5—Aryl—1,2—dihydro—1—pyrrolizinones

In order to search for new potent anti-inflammatory and analgesic agents in pyrrolizinones,the title compounds were designed and synthesized.A series of the compounds were prepared with two different synthetic schemes.Some of the compounds showed remarkable anti-inflammatory and/or analgesic activities on mice.     

EFFECTS OF MONOCLONAL ANTIBODY ANTIEGF RECEPTOR ON HUMAN NASOPHARYNGEAL CARCINOMA CELL AND OTHER TUMOR CELLS

Three anti-EGF receptor MoAbs were used in these studies. Administration of MoAbs 3 and 176 inhibited tumor formation in nude mice by CNE-2, a poorly differentiated nasopharyngeal carcinoma cell line and A431, an epidermoid carcinoma cell line. When the same MoAbs were used in treatment against HeLa, a cervical carcinoma, tumor growth was not affected. The number of EGF receptors and apparent dissociation constants for ~(125)I-EGF on CNE-2 and A431 was 1.3×10~(?)/cell (Kd 7.7×10~(-8)mol/L) and 1.4×10~6/cell(Kd 2.4×10~(-9)mol/L), respectively. Both MoAbs 3 and 176, capable of competing with EGF for receptor binding, showed significant tumor growth inhibition. MoAb 101 was incapable of blocking the binding of EGF to its receptor, and not as effective as MoAbs 3 and 176 in tumor growth inhibition. Our observation is that the MoAb anti-EGF receptor is cytostatic rather than cytocidal, in vitro against CNE-2 and A431.     

ROLE OF THIOL-DISULFIDE EXCHANGE IN INSULIN BINDING TO ITS RECEPTOR

The effects of reduction by DTT, oxidation by DTNB and treatment with NEM on the thiol contents and insulin binding to its receptor in mice liver membranes were studied. Reduction with DTT leads to a parallel increase in the thiol content and the speciflc binding of insulin to the membrane. Scatchard analysis of the results shows little change in the number of binding sites but a twofold increase of the binding constant. Washing the membrane with bound insulin by a DTT containing buffer results in a more marked increase in the release of bound insulin than washing with buffer alone, suggesting that part of the insulin is bound to its receptor by covalent disulfide linkages through a thIol-disulfide exchange reaction and reduction with DTT leads to a marked increase in this "disulfide-linked" insulin. Treatment with DTNB or NEM of the DTT-reduced membrane seems to reverse the effect of DTT reduction, although the reaction of the untreated membrane with DTNB or NEM had little or no effect on the specific     

A STUDY OF THE GLUCOCORTICOID RECEPTOR OF THE CYTOSOL AND NUCLEI IN NONLETHALLY AND LETHALLY SCALDED RATS

The glucocorticoid receptor (GCR) of the cytosol of liver and brain was studied by radioligand binding assay, using [~3H] dexamethasone (Dex) as the ligand in lethally and nonlethally scalded rats. As compared with controls, the binding capacity (R_0) was decreased and the apparent K_d of [~3H] Dex specific binding was increased in both scalded groups. In the lethal group, the R_u is much lower than that in the nonlethal group. In order to determine whether the decrease of R_0 was due to the translocation of [~3H] Dex-GCR complex into the cell nuclei, the [~3H] corticosterone (B) specific binding of the hepatic nuclei was measured by the exchange assay. There was no significant difference between the control and scalded groups. The possible mechanisms and the clinical significance of these changes were discussed.     

Cell microarray chip system for accurate,rapid diagnosis and target treatment of breast cancer cells SK-BR-3

Biometrics probe is a molecule that specifically interacts with a specific target molecule and can be detected by a specific method. Three-dimensional (3D) embedded cell scaffold in the cell array chip can affect culture cancer cells in a 3D environment with continuous medium supplementary and help controlling the diffusion of small molecules drugs. Based on modification of DNA segment, this type of cell micro-array chip is a new biochip technology with convenient focusing and high throughput screening.     

Characterization of Gallic Acid Interaction with Human Serum Albumin by Spectral and Molecular Modeling Methods

The binding of drugs with human serum albumin(HSA)is a crucial factor influencing the distribution and bioactivity of drugs in the body.To understand the action mechanisms between gallic acid(GA,3,4,5-...     

DYNORPHIN: POTENT ANALGESIC EFFECT IN SPINAL CORD OF THE RAT

Evidences are presented to show a strong and long-lasting analgesic effect after injec-tion of dynorphin into the subarachnoid space of the spinal cord in the rat. Taking theamplitude and time course of the increase of tail flick latency as the indices of analgesia,dynorphin elicited dose-dependent analgesic effect in the range of 2.3--18.6 nmol. Calcu-lating on a molar basis dynorphin was 6--10 times more potent than morphine and 65--100 times more potent than morphiceptin, another mu opiate receptor agonist. Dynorphinanalgesia was completely reversed by intrathecal injection of anti-dynorphin IgG and par-tially reversed by naloxone. Acute tolerance to morphine analgesia did not affect the occu-rance of dynorphin analgesia, indicating the absence of cross tolerance between morphineand dynorphin. Evidence from different lines of approach suggests that dynorphin may bindwith kappa opiate receptors in the spinal cord to exert its analgesic effect     

Evaluation of Drug Interaction in Binding to Protein by High Performance Liquid Chromatography

Drugs in the body are bound to metabolizing enzymes, targets/receptors and transport proteins in certain extent. The binding of drugs to targets or receptors is mainly specific and responsible for its pharmacological and therapeutic effects. The metabolizing of drugs by enzyme involves both     

MECHANISM OF INTERFERON ACTION——THE DISCOVERY OF pppA2'p5'A2'p5'A RECEPTOR

In this paper it is demonstrated that (~3H)2'-5'P_3A_3 can bind to the peritoneal macrophages from Wistar rat. This binding is strongly inhibited by cold 2'-5'P_3A_3 while the inhibiting capacity of 2'-5'P_3I_3 and 2'-5'A_3 is very small, showing that this binding is highly specific. And the binding of (~3H)2'-5'P_3A_3 is reversible, saturable and with high affinity. A Scatchard analysis of the binding data gives a linear plot, an apparent dissociation constant (Kd) about 1.3×10~(-7) M and binding sites per cell about 2.1×10~7. The above evidence shows the existence of the 2'-5'P_3A_3 receptor, a fact which, to our knowledge, has not been reported before.     

Design,synthesis and antifungal activities in vitro of novel tetralin compounds

Novel chiral tetralin compounds were designed and synthesized, and their antifungal activities in vitro were tested. The results showed that all of target compounds had potent antifungal activities, and were stronger than that of control compounds tetrahydroisoquinolines. The binding model of lead molecules in the active site of CYP51 of Candida albicans showed that lead compound specifically interacted with the amino acids residues in the active site, without binding with the heme of CYP51, which was different from azole antifungal drugs. The present study might afford a novel lead molecule to develop non-azole CYP51 inhihitars of fungi.     

Preparation and Application of an Immunoaffinity Column for Direct Extraction of Morphine and its Analogs from Opium

A rapid, simple and accurate method using an immunoaffinity column (IAC) andcapillary electrophoresis (CE) for the analysis of the major alkaloids in opium is developed. TheIAC was synthesized by coupling specific morphine polyclonal antibodies to CNBr-activedSepharose 4B. The IAC showed high selectivity and obvious enrichment to morphine, codeine,dionin and thebaine. The extraction solution was analyzed by CE with J3-cyclodextrin as anadditive. Recoveries of the four alkaloids from PBS were between 93%-105% with RSD valueless than 5.0%. The result showed that this method was practical for the determination ofmorphine analogs in opium.     

Application of liquid pre-column capillary electrophoresis technique to the study of interaction between drug enantiomers and human serum albumin

Based on the chiral separation of several basie drugs, dimetindene, tetryzoline, theodrenaline and verapamil, the liquid pre-colunm capillary electrophoresis (LPC-CE) technique was established. It was used to determine free concentrations of drug enantiomers in mixed solutions with human serum albumin (HSA). To prevent HSA entering the CE chiral separation zone, the mobility differences between HSA and drugs under a specific pH condition were employed in the LPC. Thus, the detection confusion caused by protein was totally avoided. Further study of binding constants determination and protein binding competitions was carried out. The study proves that the LPC technique could be used for complex media, particularly the matrix of protein coexisting with a variety of drugs.     

REGULATION OF GLUCOCORTICOID RECEPTOR BY GLUCOCORTICOIDS(Ⅱ) ——THE STUDIES ON RAT LIVER, BRAIN AND SPLEEN

The concentration of glucocorticoids (GC) in plasma was maintained at stress level, 20--40μg/dl, for 3 days by subcutaneous injection of hydrocortisone (F) in polyvinyl alcohol (PVA) into rats, and the specific binding of [~3H]Dexamethasone (Dex) in liver, spleen and brain was determined before and after injection. The binding capacity of glucocorticoid receptor (GR) in liver and spleen was decreased significantly 1 h after injection and maintained at low level for several days after the concentration of GC in plasma had returned to the normal level. The K_d was not altered. The changes of GR in brain was not significant. Thus it may be concluded that GC can down-regulate GR in rats, but with different characteristics in various target organs.     

A High Performance Theory for Thermodynamic Study on the Binding of Human Serum Albumin with Erbium Chloride

A thermodynamic study of the interaction between erbium(III) chloride (Er3＋) and human serum albumin (HSA) was studied at pH＝7.0, 27 and 37 ℃ in phosphate buffer by isothermal titration calorimetry (ITC). The present study reports the thermodynamic parameters that govern HSA-Er3＋ interactions. The extended solvation theory was used to reproduce the enthalpies of HSA-Er3＋ interactions over the whole range of Er3＋ concentrations. The binding parameters recovered from the new model were attributed to the structural change of HSA and its biological activity. The results obtained indicate that there is a set of two identical binding sites for Er3＋ ions with negative cooperativity. The enhancement of complex formation by Er3＋ and concomitant increase in ∆S suggest that the metal ion plays a role in increasing the number of hydrophobic contacts. The binding parameters discovered from the extended solvation model indicate that the stability of HSA molecule is increased as a result of its interaction with Er3＋ ions.     

Determination of trace amounts of morphine in human plasma by anodic adsorptive stripping differential pulse voltammetry

New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation of morphine on a HMDE,followed by oxidation of adsorbed morphine by voltammetry scan using differential pulse modulation.The optimum conditions for the analysis of morphine are pH 10.5,Eacc of -100 mV（vs.Ag/AgCl）,and tacc of 120 s.The peak current is proportional to the concentration of morphine,and a Linear calibration graph is obtained at 0.01-3.10μg mL^-1.A relative standard deviation of 1.06%（n=5）was obtained,and the limit of detection was 3 ng mL^-1.The capabiLity of the method for the analysis of real samples was evaluated by the determination of morphine in spiked human plasma and addicts human plasma with satisfactory results.     

Binding studies of DNA with Co(Ⅲ) coordination compound

The binding of Co(bpy)2dppz3+ to calf thymus DNA was investigated by using absorption and emission spectroscopy,DNA melting techniques,cyclic voltammetry,viscosity and electro-phoresis measurements,where bpy is 2,2'-bipyridyl,dppz is dipyrido[3,2-o:2',3'-c] phenazine.The binding compound shows absorption hypochromicity,fluorescence enhancement,and increasing of DNA melting temperature and the specific viscosity.CV measurement shows the shifts in oxidation-reduction potential and change in peak current with addition of DNA.The compound is also shown to be more efficient photosensitisers for strand breaks in plasmid DNA.