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Monteillet-Agius G, Fein J, Anton B, Evans CJ. ORL-1 and mu opioid receptor antisera label different fibers in areas involved in pain processing. J Comp Neurol 1998; 399:373-83. [PMID: 9733084 DOI: 10.1002/(sici)1096-9861(19980928)399:3<373::aid-cne6>3.0.co;2-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mu opioid receptors (MOR) mediate the analgesic effects of opioid drugs such as morphine. The opioid receptor-like (ORL-1) receptor is structurally related to opioid receptors and the ORL-1 receptor agonist, orphanin FQ/nociceptin, induces analgesia at the spinal level, but appears to recruit different circuitry than that used by mu opioids. When administered intracerebroventricularly, orphanin FQ/nociceptin produces hyperalgesia and/or reverses opioid analgesia. The functionally distinct actions elicited by MOR and ORL-1 receptors, which activate similar intracellular signaling systems and show similar regional distributions, could be explained by their differential cellular localization. By using double label immunohistochemistry and confocal microscopy, the present study investigates the distribution of MOR and ORL-1 receptors in regions of the rat nervous system that are involved with nociceptive processing. In general co-localization of MOR and ORL-1 receptor immunoreactivity was not observed in either perikarya or neuropil in the dorsal root ganglia, nor in the Lissauer's tract and superficial laminae of the spinal cord. Likewise, there was no evidence for co-localization of these receptors within the periaqueductal gray, the nucleus raphe magnus, the gigantocellular reticular nucleus, and the nucleus of the solitary tract. These observations indicate that MOR and ORL-1 receptors are expressed predominantly on different fiber systems in these regions. This differential distribution is consistent with the distinct pharmacology of ORL-1 and MOR receptor agonists and suggests that the antisera to MOR and ORL-1 receptors may provide useful markers for further investigations of analgesic and counteranalgesic pathways modulating pain perception.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal
- Antibody Specificity
- Fluorescent Antibody Technique
- Ganglia, Spinal/chemistry
- Ganglia, Spinal/cytology
- Ganglia, Spinal/physiology
- Immunoenzyme Techniques
- Male
- Molecular Sequence Data
- Nerve Fibers/chemistry
- Nerve Fibers/physiology
- Nociceptors/physiology
- Pain/metabolism
- Periaqueductal Gray/chemistry
- Periaqueductal Gray/cytology
- Periaqueductal Gray/physiology
- Raphe Nuclei/chemistry
- Raphe Nuclei/cytology
- Raphe Nuclei/physiology
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid/analysis
- Receptors, Opioid/genetics
- Receptors, Opioid/immunology
- Receptors, Opioid, mu/analysis
- Receptors, Opioid, mu/immunology
- Solitary Nucleus/chemistry
- Solitary Nucleus/cytology
- Solitary Nucleus/physiology
- Spinal Cord/chemistry
- Spinal Cord/cytology
- Spinal Cord/physiology
- Nociceptin Receptor
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77
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Murray SR, Evans CJ, von Zastrow M. Phosphorylation is not required for dynamin-dependent endocytosis of a truncated mutant opioid receptor. J Biol Chem 1998; 273:24987-91. [PMID: 9737953 DOI: 10.1074/jbc.273.39.24987] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Opioid receptors are regulated within minutes after activation by G protein-coupled receptor kinase-mediated phosphorylation and dynamin-dependent endocytosis. We addressed the question of whether phosphorylation is required for opioid receptor endocytosis by examining a functional, truncated mutant delta opioid receptor (DOR344T), which is missing phosphorylation sites located in the carboxyl-terminal cytoplasmic domain. DOR344T receptors expressed in Chinese hamster ovary cells remained predominantly in the plasma membrane, even in the presence of saturating concentrations of agonist, consistent with previous studies demonstrating strongly inhibited endocytosis of truncated receptors in this cell type. In marked contrast, DOR344T receptors expressed at similar levels in human embryonal kidney (HEK) 293 cells exhibited rapid, ligand-induced internalization either in the presence of peptide (DADLE) or alkaloid (etorphine) agonist. Quantitative assays using ELISA and flow cytometric techniques indicated that DOR344T receptors were endocytosed in HEK293 cells with similarly rapid kinetics as full-length DOR (t1/2 < 10 min), and both full-length DOR and DOR344T mutant receptors were endocytosed by a dynamin-dependent mechanism involving clathrin-coated pits. Nevertheless, DOR344T receptors failed to undergo any detectable constitutive or agonist-induced phosphorylation in the same cells in which dynamin-dependent endocytosis was observed. These findings establish the first example of a G protein-coupled receptor that does not require phosphorylation to undergo dynamin-dependent endocytosis, and they suggest that significant cell type-specific differences exist in the biochemical requirements for ligand-induced concentration of opioid receptors in clathrin-coated pits.
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78
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Parks RE, Shao L, Evans CJ. Pixel-based absolute topography test for three flats. APPLIED OPTICS 1998; 37:5951-5956. [PMID: 18286090 DOI: 10.1364/ao.37.005951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We demonstrate a method of performing the absolute three-flat test by using reflection symmetries of the surfaces and an algorithm for generating the rotation of arrays of pixel data. Most of the operations involve left/right and top/bottom flips of data arrays, operations that are very fast on most frame grabbers and are available on most commercial phase-measuring interferometers. We demonstrate the method with simulated data as well as with actual data from 150-mm-diameter surfaces that are flat to less than 25 nm peak to valley.
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79
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Unterwald EM, Anton B, To T, Lam H, Evans CJ. Quantitative immunolocalization of mu opioid receptors: regulation by naltrexone. Neuroscience 1998; 85:897-905. [PMID: 9639282 DOI: 10.1016/s0306-4522(97)00659-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study utilized a newly developed quantitative immunohistochemical assay to measure changes in mu opioid receptor abundance following chronic administration of the opioid receptor antagonist naltrexone. These data were compared with those obtained from mu receptor radioligand binding on adjacent tissue sections, in order to determine whether the characteristic antagonist-induced increase in radioligand binding is due to an increase in the total number of mu receptors and/or to an increase in the proportion of receptors that are in an active binding conformation in the absence of a change in the total number of receptors. Adult male Sprague-Dawley rats were administered naltrexone, 7-8 mg/kg per day, or saline continuously for seven days by osmotic minipumps, after which time their brains were processed for immunohistochemistry and receptor autoradiography on adjacent fresh frozen tissue sections. Semiquantitative immunohistochemistry was performed using a radiolabelled secondary antibody for autoradiographic determination and a set of radioactive standards. Results demonstrate an overall concordance between the distribution of mu opioid receptors as measured by the two different methods with a few exceptions. Following naltrexone administration, mu receptor immunoreactivity was significantly higher in the amygdala, thalamus, hippocampus, and interpeduncular nucleus as compared with the saline-treated control animals. [3H]D-Ala2,N-Me-Phe4,Gly-ol5-enkephalin binding to mu opioid receptors was significantly higher in the globus pallidus, amygdala, thalamus, hypothalamus, hippocampus, substantia nigra, ventral tegmental area, central gray, and interpeduncular nucleus of the naltrexone-treated rats. These findings indicate that in some brain regions chronic naltrexone exposure increases the total number of mu opioid receptors, while in other regions there is an increase in the percent of active receptors without an observable change in the total number of receptors. Quantitative receptor immunodetection together with ligand autoradiography provides a new approach for investigating the regulation of mu opioid receptors on tissue sections.
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80
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Evans CJ, Petö GC, al-Lehyani S, Darko JB. The elemental analysis of the human body using associated particle timing based on the D + D reaction. Appl Radiat Isot 1998; 49:549-51. [PMID: 9569539 DOI: 10.1016/s0969-8043(97)00072-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fast (approximately 2.8 MeV) neutrons are generated in the 2H(d,n)3He reaction, and are used for excitation of sample materials via inelastic scattering. Nanosecond timing identifies the spatial origin of the measured gamma radiation, making possible three-dimensional imaging and improved detection sensitivity. Several elements have been measured, and it is estimated that a clinical device, with equivalent dose of 10 mSv, will be capable of detecting the order of 10-100 mg.
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81
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Evans CJ, Shamsaie M, Ghara'ati H, Ali PA. A new Monte Carlo program for computing low-energy gamma- and X-ray propagation in an axially-symmetric XRF system. Swansea In Vivo Analysis and Cancer (SIVAC) Group. Appl Radiat Isot 1998; 49:559-60. [PMID: 9606085 DOI: 10.1016/s0969-8043(97)00187-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Annular XRF systems, using backscattering geometry, have advantages of convenience of use, but it is difficult to predict their sensitivity to concentrations of heavy metals ta different depths, or the contribution of scattered radiation to the background. A Monte Carlo program has therefore been developed to carry out calculations of this type. Several variance-reduction techniques are included. Preliminary results for the detection of platinum are given.
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82
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Ryde SJ, Eston R, Laskey MA, Evans CJ, Hancock DA. Changes in body fat: measurements by neutron activation, densitometry and dual energy X-ray absorptiometry. Appl Radiat Isot 1998; 49:507-9. [PMID: 9569529 DOI: 10.1016/s0969-8043(97)00062-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The measurement of body fat in ten subjects (BMI from 22 to 43 kg/m2), and in particular the changes arising from a ketogenic diet, by the techniques of in vivo neutron activation analysis (NAA), densitometry (using two- and four-compartment models) by under water weighing (UWW) and dual energy X-ray absorptiometry (DXA) was compared. The association between techniques for the fat changes was generally high (r = 0.70 to 0.98) and significant (p < 0.05). Assessment of agreement between DXA and the other techniques revealed discrepancies with significant slope and high association (r = -0.81 and -0.64). Whilst NAA and UWW appeared to measure similar changes, DXA underestimated small changes.
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83
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Ali PA, al-Ghorabie FH, Evans CJ, el-Sharkawi AM, Hancock DA. Body composition measurements using DXA and other techniques in tamoxifen-treated patients. Appl Radiat Isot 1998; 49:643-5. [PMID: 9569566 DOI: 10.1016/s0969-8043(97)00082-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tamoxifen is an anti-oestrogenic drug which is widely used in the treatment of patients with breast cancer. There is increasing interest in using the drug both for benign breast disease and as a chemo-preventative agent of the drug in women at high risk of breast cancer. Despite the fact that the acute side-effects of the drug are few, its agonistic and antagonistic oestrogenic effects are not fully known and may have some undesirable effects for patients treated with the drug for several years. A number of studies carried out recently indicate a varying degree of change in bone mineral content following treatment with tamoxifen. These studies concentrated mainly on bone mineral density measurements only and non of them reported the effects of tamoxifen on lean body mass and fat mass. In this study we measured lean body mass and fat mass in tamoxifen-treated females and a comparison group to determine the difference between the two groups. Twenty-six women receiving tamoxifen (20 mg/d) have participated in this study. The control group comprised 31 healthy women of a similar age. Total body bone mineral (TBBM) was measured using a dual-energy X-ray absorptiometry (DXA) (Hologic INV., Waltham, U.S.A.). Similarly, regional and total body soft tissue (lean and fat tissue) were measured using the DXA system. In addition to DXA measurements, percentage body fat (%BF) was measured using total body potassium counting (TBK), skinfold anthropometry (SF), infrared interactance (i.r.) and bioelectric impedance analysis (BIA). Results from DXA alone showed that there were no significant differences between the two groups for TBBM, regional and total body lean tissue mass. However, there was a significant difference between the two groups (P < 0.05) for %BF measurement. Similarly there was a significant difference between the two groups (P < 0.05) for %BF measured by other body composition techniques. Although there is no other research reported on the effects of tamoxifen on %BF, this retrospective study indicates that tamoxifen may lead to increase in fact content in women who are subjected to this treatment. We conclude that this observation is probably related to the agonistic oestrogenic effect of Tamoxifen on body fat. To our knowledge this deleterious effect has not been reported before and it should be taken into considerable when comprising different types of anti-oestrogenic drugs. Furthermore, patients should be warned about this side-effect when they are prescribed Tamoxifen therapy.
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84
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Evans CJ, Ryde SJ, Hancock DA, al-Agel F. Monte Carlo simulation of prompt gamma neutron activation analysis using MCNP code. Appl Radiat Isot 1998; 49:541-3. [PMID: 9569538 DOI: 10.1016/s0969-8043(97)00071-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Prompt gamma neutron activation analysis (PGNAA) is the most direct method of measuring total-body nitrogen. In combination with internal hydrogen standardisation, it is possible to reduce the dependence on body habitus. The uniformity of activation and detection, however, cannot be optimised sufficiently to eliminate the dependence entirely, and so further corrections are essential. The availability of the powerful Monte Carlo code MCNP(4A) has allowed a more accurate analysis of the activation facility, and yields corrections for body habitus and superficial fat layers. The accuracy of the correction is retained as the source-to-skin distance is reduced, although the activation uniformity is thereby degraded. This allows the use of a 252Cf source with lower activity and hence reduces the running cost of the facility.
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85
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Keith DE, Anton B, Murray SR, Zaki PA, Chu PC, Lissin DV, Monteillet-Agius G, Stewart PL, Evans CJ, von Zastrow M. mu-Opioid receptor internalization: opiate drugs have differential effects on a conserved endocytic mechanism in vitro and in the mammalian brain. Mol Pharmacol 1998; 53:377-84. [PMID: 9495801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
mu-Opioid receptors are the pharmacological targets of endogenous opioid peptides and morphine-like alkaloid drugs. Previous studies of transfected cells and peripheral neurons indicate that opioid receptors are rapidly internalized after activation by the alkaloid agonist etorphine but not after activation by morphine. To determine whether opioid receptors in the central nervous system are regulated by a similar process of agonist-selective internalization, mu-opioid receptors were examined in rat brain neurons after treatment of animals with opioid drugs. Internalized mu receptors were observed within 30 min after intraperitoneal injection of the alkaloid agonist etorphine, and this process was blocked by the antagonist naloxone. Colocalization of internalized opioid receptors with transferrin receptors in confocal optical sections indicated that receptor internalization observed in vivo is mediated by a membrane trafficking pathway similar to that observed previously in vitro using transfected human embryonic kidney 293 cells. Morphine failed to induce detectable rapid internalization of receptors, even when administered to animals at doses far in excess of those required to induce analgesia. To quantify these agonist-selective differences and to analyze an array of opioid ligands for their ability to trigger internalization, we used flow cytometry on stably transfected 293 cells. These studies indicated that the different effects of individual agonists are not correlated with their potencies for receptor activation and that a variety of clinically important agonists differ significantly in their relative abilities to stimulate the rapid internalization of opioid receptors.
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86
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Lo EH, Pierce AR, Matsumoto K, Kano T, Evans CJ, Newcomb R. Alterations in K+ evoked profiles of neurotransmitter and neuromodulator amino acids after focal ischemia-reperfusion. Neuroscience 1998; 83:449-58. [PMID: 9460753 DOI: 10.1016/s0306-4522(97)00434-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Secondary elevations in extracellular amino acids occur during reperfusion after transient cerebral ischemia. The delayed accumulation of excitatory amino acids may contribute to the progressive development of neuronal injury. In this study, we explored the mechanisms that may be involved in this phenomenon. Microdialysis samples from probes located in rabbit cortex were analysed with a chiral amino acid procedure. Concentrations of neurotransmitters (L-Glu, GABA), N-methyl-D-aspartate receptor modulators (D-Ser, Gly), an inhibitory neuromodulator (Tau), the lipid component phosphoethanolamine, and L-Gln, L-Ser and L-Ala were measured. Depolarization via perfusion with potassium was used to assess the status of release/reuptake systems at 2 and 4 h reperfusion after 2 h transient focal ischemia. Background experiments classified potassium evoked responses as calcium dependent or calcium-independent by inclusion of 30 microM omega-conopeptide MVIIC or by inclusion of 20 mM magnesium and ommision of calcium. During ischemia, large elevations of almost all amino acids occurred. During reperfusion, secondary elevations in transmitter amino acids (L-Glu, GABA) and N-methyl-D-aspartate receptor modulators (D-Ser, Gly) occurred. Tau remained slightly elevated whereas the lipid component phosphoethanolamine remained high and stable during reperfusion. Reperfusion significantly potentiated the potassium response for amino acids with calcium-dependent responses (L-Glu and GABA). In contrast, calcium-independent responses (Tau, phosphoethanolamine, L-Gln) were significantly attenuated. Intermediate behavior was observed with Gly, while no potassium responses were observed for D-Ser, L-Ser or L-Ala. These data demonstrate that perturbations in evoked amino acid profiles after ischemia-reperfusion are selective. Reduction of calcium-independent responses implicate a general decline in efficacy of transporter mechanisms that restore transmembrane gradients of ions and transmitters. Decreased efficacy of transporter systems may reduce transmitter reuptake and account for the amplified release of L-Glu and GABA, thus contributing to progressive neural dysfunction after cerebral ischemia.
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87
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Evans CJ, McGee C. Collaboration between a state alliance for the mentally ill and a state mental health authority in monitoring the consequences of downsizing. J Behav Health Serv Res 1998; 25:43-50. [PMID: 9516293 DOI: 10.1007/bf02287499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
As consumers are released from hospitalization as a result of the downsizing of inpatient psychiatric facilities, their ability to sustain themselves in the community becomes a concern to a number of constituencies. This article describes the development of a program for monitoring persons who were released from hospitals into the community as a result of the downsizing of state psychiatric hospitals. The program's uniqueness was the collaboration between the state mental health authority and the state Alliance for the Mentally Ill in developing and implementing the monitoring system.
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88
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Evans CJ, McNaughton D, Dexter P, Lawrance W. High-Resolution Fourier Transform Infrared Spectroscopy of Nitrosyl Fluoride. JOURNAL OF MOLECULAR SPECTROSCOPY 1998; 187:75-81. [PMID: 9473423 DOI: 10.1006/jmsp.1997.7470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The high-resolution FTIR spectrum of FNO has been recorded and the rovibrational structure of the essentially unperturbed nu3, 2nu3, and nu1 + nu3 cold bands and the 2nu3 <-- nu3, nu2 + nu3 <-- nu3, and nu1 + nu2 + nu3 <-- nu3 hot bands has been analyzed. The perturbed bands nu1 and nu1 + nu2 have been assigned and the data analyzed by fitting the transitions with the dark states nu2 + 2nu3 and 2nu2 + 2nu3. Parameters for both light and dark states together with Coriolis coupling parameters have been determined. Copyright 1998 Academic Press. Copyright 1998Academic Press
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89
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Thomas DW, Ryde SJ, Ali PA, Birks JL, Evans CJ, Saunders NH, Al-Zeibak S, Dutton J, Hancock DA. The performance of an infra-red interactance instrument for assessing total body fat. Physiol Meas 1997; 18:305-15. [PMID: 9413864 DOI: 10.1088/0967-3334/18/4/004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Infra-red interactance has been evaluated as a technique for measuring total body fat in comparison with a range of alternative methods. The alternative techniques employed were neutron activation analysis, tritiated water dilution, whole-body potassium-40 counting, skinfold anthropometry, bioelectrical impedance analysis and the body mass index. The study group consisted of 43 healthy adults (16 males and 27 females). For 11 women, measurements were obtained before and after 11 weeks on a very low-calorie diet, giving a total of 54 sets of data. Correlation coefficients between infra-red interactance and the other techniques varied between 0.58 (p < 0.0002) and 0.80 (p < 0.0001) for females, and between 0.64 (p < 0.009) and 0.94 (p < 0.0001) for males. The average fat for the study group was underestimated by 15% using infra-red interactance in comparison with the average fat obtained from the other techniques. It was also noted that the infra-red interactance instrument yielded a very narrow range of body fats in females in comparison with the other techniques. It is essential that these differences are reconciled before infra-red interactance takes a significant role in body composition analysis.
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90
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Olive MF, Anton B, Micevych P, Evans CJ, Maidment NT. Presynaptic versus postsynaptic localization of mu and delta opioid receptors in dorsal and ventral striatopallidal pathways. J Neurosci 1997; 17:7471-9. [PMID: 9295393 PMCID: PMC6573463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/1997] [Revised: 06/26/1997] [Accepted: 07/21/1997] [Indexed: 02/05/2023] Open
Abstract
Parallel studies have demonstrated that enkephalin release from nerve terminals in the pallidum (globus pallidus and ventral pallidum) can be modulated by locally applied opioid drugs. To investigate further the mechanisms underlying these opioid effects, the present study examined the presynaptic and postsynaptic localization of delta (DOR1) and mu (MOR1) opioid receptors in the dorsal and ventral striatopallidal enkephalinergic system using fluorescence immunohistochemistry combined with anterograde and retrograde neuronal tracing techniques. DOR1 immunostaining patterns revealed primarily a postsynaptic localization of the receptor in pallidal cell bodies adjacent to enkephalin- or synaptophysin-positive fiber terminals. MOR1 immunostaining in the pallidum revealed both a presynaptic localization, as evidenced by punctate staining that co-localized with enkephalin and synaptophysin, and a postsynaptic localization, as evidenced by cytoplasmic staining of cells that were adjacent to enkephalin and synaptophysin immunoreactivities. Injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) or the retrograde tracer Texas Red-conjugated dextran amine (TRD) into the dorsal and ventral striatum resulted in labeling of striatopallidal fibers and pallidostriatal cell bodies, respectively. DOR1 immunostaining in the pallidum co-localized only with TRD and not PHA-L, whereas pallidal MOR1 immunostaining co-localized with PHA-L and not TRD. These results suggest that pallidal enkephalin release may be modulated by mu opioid receptors located presynaptically on striatopallidal enkephalinergic neurons and by delta opioid receptors located postsynaptically on pallidostriatal feedback neurons.
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91
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Gylys KH, Tran N, Magendzo K, Zaki P, Evans CJ. cAMP decreases steady-state levels of delta-opioid receptor mRNA in NG108-15 cells. Neuroreport 1997; 8:2369-72. [PMID: 9243642 DOI: 10.1097/00001756-199707070-00053] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have compared several drug combinations for their ability to increase basal cAMP and to down-regulate delta-opioid receptor mRNA levels. Continuous treatment for up to 48 h with a phosphodiesterase inhibitor in combination with the adenylyl cyclase activator forskolin showed an early peak response, but cAMP levels returned to control after 8 and 24 h. Increases in cAMP level up to 150-fold were observed after treatment for 1 h with a series of drugs (rolipram, IBMX/forskolin, rolipram/forskolin, dibutyryl cAMP, and prostaglandin E2) that increase cAMP by different mechanisms. A significant decrease in DOR mRNA level, to 31% of control, followed the three treatments that produced the largest increases in cAMP level: IBMX/forskolin, rolipram/forskolin, and prostaglandin E2.
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92
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Lewis DG, Natto SS, Ryde SJ, Evans CJ. Monte Carlo design study of a moderated 252Cf source for in vivo neutron activation analysis of aluminium. Phys Med Biol 1997; 42:625-36. [PMID: 9127441 DOI: 10.1088/0031-9155/42/4/002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Monte Carlo computer code MCNP has been used to design a moderated 252Cf neutron source for in vivo neutron activation analysis of aluminium (Al) in the bones of the hand. The clinical motivation is the need to monitor Al body burden in subjects with renal dysfunction, at risk of Al toxicity. The design involves the source positioned on the central axis at one end of a cylindrical deuterium oxide moderator. The moderator is surrounded by a graphite reflector, with the hand inserted at the end of the moderator opposing the source. For a 1 mg 252Cf source, 15 cm long x 20 cm radius moderator and 20 cm thick reflector, the estimated minimum detection limit is 0.5 mg Al for a 20 min irradiation, with an equivalent dose of 16.5 mSv to the hand. Increasing the moderator length and/or introducing a fast neutron filter (for example silicon) further reduces interference from fast-neutron-induced reactions on phosphorus in bone, at the expense of decreased fluence of the thermal neutrons which activate Al. Increased source strengths may be necessary to compensate for this decreased thermal fluence, to allow measurements to be made within an acceptable time limit for the comfort of the patient.
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93
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Evans CJ, Petö GC, al-Lehyani S, Darko JB. The use of associated particle timing based on the D + D reaction for elemental analysis of bulk samples such as the human body. Appl Radiat Isot 1997; 48:257-66. [PMID: 9219344 DOI: 10.1016/s0969-8043(96)00181-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The use of associated particle timing based on the D + D reaction has been demonstrated for elemental analysis of bulk samples such as the human body. The neutron energy of 2.8 MeV eliminates the background from organic matrices. The nanosecond timing of a HPGe detector renders it possible to identify the spatial origin of the measured gamma radiation limiting the sensitive area to a single pixel. By this technique the background could be reduced by a factor of > or = 1000, but the present set-up has achieved an effective factor only in the range 20-100, due to losses in the generation of timing signals. The very clean gamma-spectra obtained permit the use of high efficiency scintillation detectors. Sensitivities for measuring Al, Ti, and Fe are presented at an extrapolated dose of 10 mSv.
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94
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Rocha LL, Evans CJ, Maidment NT. Amygdala kindling modifies extracellular opioid peptide content in rat hippocampus measured by microdialysis. J Neurochem 1997; 68:616-24. [PMID: 9003048 DOI: 10.1046/j.1471-4159.1997.68020616.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Opioid peptide release in the hippocampus was shown to be increased immediately following amygdala kindling stimulation in freely moving rats using microdialysis combined with a universal opioid peptide radioimmunoassay (RIA). Extracellular opioid peptide levels were elevated (55% above basal levels) within the first 10 min after electrical stimulation-induced partial seizures in previously nonkindled animals. Fully kindled rats showed lower extracellular opioid peptide levels (40% reduction) during the interictal period [16 +/- 2.1 days (mean +/- SEM) after the last stage V seizure], in comparison with values obtained from the sham-kindled group under basal conditions. However, opioid peptide release in fully kindled rats increased above 152% of interictal levels within the first 20 min after onset of fully kindled seizures, attaining peak levels equal to that of the partial kindled group and returning to prestimulation conditions 40-60 min following the ictal events. The majority of the immunoreactive material recovered from the hippocampus within the first 20 min following partial and generalized kindled seizures coeluted with dynorphin-A (1-6), dynorphin-A (1-8), and Leu-enkephalin by HPLC/RIA analysis. It is proposed that the enhanced opioid peptide release in hippocampus induced by amygdala kindling stimulation might be associated with either enhanced excitability or seizure suppression as seizure susceptibility fluctuates. The reduced interictal opioid peptide levels may also underlie some interictal behavioral disturbances.
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95
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Abstract
It is known that opioid peptides acting on opioid receptors can modulate hippocampal synaptic functions. Although a novel member of the opioid receptor family, ORL1 receptors, that displays high-sequence homology with classical opioid receptors is abundant in the hippocampus, little is known regarding its role in synaptic function. The present study was designed to investigate whether activation of the ORL1 receptor by its natural ligand, orphanin FQ, could modulate synaptic transmission and synaptic plasticity in the hippocampus. The actions of orphanin FQ in the CA1 and dentate gyrus were examined by field potential recordings in response to stimulation of Schaffer collaterals and perforant path, respectively. Our results showed that orphanin FQ, but not the inactive analog des-Phe1-orphanin FQ, reduced both the slope of the excitatory postsynaptic potentials and population spike amplitude. The inhibitory effect of orphanin FQ is dose dependent and probably involves a presynaptic mechanism, as suggested by the significantly increased paired-pulse facilitation evoked in the presence of orphanin FQ. In addition, orphanin FQ was found to inhibit the induction of long-term potentiation at the Schaffer collateral-CA1 synapse. These results demonstrate that orphanin FQ can function as an inhibitory modulator regulating synaptic transmission and synaptic plasticity in the hippocampus, suggesting that activation of ORL1 receptors may play an important role in synaptic plasticity involved in learning and memory.
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96
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Rocha L, Briones M, Ackermann RF, Anton B, Maidment NT, Evans CJ, Engel J. Pentylenetetrazol-induced kindling: early involvement of excitatory and inhibitory systems. Epilepsy Res 1996; 26:105-13. [PMID: 8985692 DOI: 10.1016/s0920-1211(96)00046-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Alterations in the brain of rats receiving a single non-convulsive administration pentylenetetrazol (PTZ), 30 mig/kg, i.p. (single PTZ group) were investigated and compared with those detected in fully PTZ kindled rats (chronic PTZ group). In vitro receptor autoradiography experiments showed that both single and chronic PTZ groups presented mu opioid and benzodiazepine (BDZ) receptor binding in specific brain areas. Using an antibody generated against the delta opioid receptor (DOR-1), it was found that DOR-1 like immunoreactivity was reduced in cortex and amygdala in mice following single and chronic PTZ administration. Microdialysis experiments revealed that the administration of PTZ 30 mg/kg, i.p. in freely moving rats without previous experience with the drug, induces a rise in glutamate release, detected in the first and second 10 min dialysates collected from amygdala (138% and 50%, respectively) and frontal cortex (70% and 45%, respectively) as well as aspartate in frontal cortex in the first and second PTZ-dialysates (143% and 80%, respectively). Subsequently, values returned to basal conditions. It may be speculated that decreased BDZ receptor binding results from enhanced release of GABA. On the other hand, the decrease of mu receptor binding and DOR-1 immunoreactivity observed after PTZ administration may be the result of enhanced levels of opioid peptides probably released over the kindling procedure. In conclusion, the present study indicates that PTZ-kindling is associated with an imbalance between excitatory and inhibitory systems which is apparent early in the epileptogenic process.
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97
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Trapaidze N, Keith DE, Cvejic S, Evans CJ, Devi LA. Sequestration of the delta opioid receptor. Role of the C terminus in agonist-mediated internalization. J Biol Chem 1996; 271:29279-85. [PMID: 8910588 PMCID: PMC3856721 DOI: 10.1074/jbc.271.46.29279] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The primary structure of the opioid receptors have revealed that many of the structural features that are conserved in other G protein-coupled receptors are also conserved in the opioid receptors. Upon exposure to agonists, some G protein-coupled receptors internalize rapidly, whereas other structurally homologous G protein-coupled receptors do not. It is not known whether opioid receptors are regulated by rapid endocytosis. In transfected Chinese hamster ovary cells expressing the epitope-tagged wild type delta opioid receptor, exposure to 100 nM [D-Ala2,D-Leu5]enkephalin causes internalization of the receptor within 30 min as determined by confocal microscopy. The rate of internalization of the wild type receptor is rapid with a half-maximal reduction by about 10 min, as determined by the reduction in mean surface receptor fluorescence intensity measured using flow cytometry. In contrast, the cells expressing receptors lacking the C-terminal 15 or 37 amino acids exhibit a substantially slower rate of internalization. Furthermore, the cells expressing receptors with point mutations of any of the Ser/Thr between Ser344 and Ser363 in the C-terminal tail exhibit a significant reduction in the rate of receptor internalization. These results suggest that a portion of the C-terminal tail is involved in receptor internalization. Agents that block the formation of clathrin-coated pits considerably reduce the extent of agonist-mediated internalization of the wild type receptor. Taken together, these results suggest that the wild type opioid receptor undergoes rapid agonist-mediated internalization via a classic endocytic pathway and that a portion of the C-terminal tail plays an important role in this internalization process.
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MESH Headings
- Amino Acid Sequence
- Animals
- CHO Cells
- Cricetinae
- DNA, Complementary
- Down-Regulation
- Endocytosis
- Enkephalin, Leucine-2-Alanine/pharmacology
- Mice
- Microscopy, Confocal
- Microscopy, Fluorescence
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
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98
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Abstract
Polymerase chain reaction was used to determine whether opioid receptor-like sequences are present in species from the protostome and deuterostome branches of the metazoan kingdom. Multiple opioid receptor-like sequences were found in all vertebrates, but no specific fragments were obtained from any invertebrates. Delta, mu, kappa and ORL-1 receptors were identified from bovine DNA, and three different opioid receptor-like fragments were identified from the other vertebrates analyzed. The data suggest that the opioid receptor gene family has been highly conserved during vertebrate evolution and that, even in the primitive jawless fish, multiple members of the opioid receptor family appear to be present.
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99
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Piros ET, Hales TG, Evans CJ. Functional analysis of cloned opioid receptors in transfected cell lines. Neurochem Res 1996; 21:1277-85. [PMID: 8947917 DOI: 10.1007/bf02532368] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Opioids modulate numerous central and peripheral processes including pain perception neuroendocrine secretion and the immune response. The opioid signal is transduced from receptors through G proteins to various different effectors. Heterogeneity exists at all levels of the transduction process. There are numerous endogenous ligands with differing selectivities for at least three distinct opioid receptors (mu, delta, kappa). G proteins activated by opioid receptors are generally of the pertussis toxin-sensitive Gi/Go class, but there are also opioid actions that are thought to involve Gq and cholera toxin-sensitive G proteins. To further complicate the issue, the actions of opioid receptors may be mediated by G-protein alpha subunits and/or beta gamma subunits. Subsequent to G protein activation several effectors are known to orchestrate the opioid signal. For example activation of opioid receptors increases phosphatidyl inositol turnover, activates K+ channels and reduces adenylyl cyclase and Ca2+ channel activities. Each of these effectors shows considerable heterogeneity. In this review we examine the opioid signal transduction mechanism. Several important questions arise: Why do opioid ligands with similar binding affinities have different potencies in functional assays? To which Ca2+ channel subtypes do opioid receptors couple? Do opioid receptors couple to Ca2+ channels through direct G protein interactions? Does the opioid-induced inhibition of vesicular release occur through modulation of multiple effectors? We are attempting to answer these questions by expressing cloned opioid receptors in GH3 cells. Using this well characterized system we can study the entire opioid signal transduction process from ligand-receptor interaction to G protein-effector coupling and subsequent inhibition of vesicular release.
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MESH Headings
- Animals
- Cell Line
- Cyclic AMP/metabolism
- GTP-Binding Proteins/metabolism
- Humans
- Inositol Phosphates/metabolism
- Models, Biological
- Narcotics/pharmacology
- Receptors, Opioid/biosynthesis
- Receptors, Opioid/physiology
- Receptors, Opioid, delta/biosynthesis
- Receptors, Opioid, delta/physiology
- Receptors, Opioid, kappa/biosynthesis
- Receptors, Opioid, kappa/physiology
- Receptors, Opioid, mu/biosynthesis
- Receptors, Opioid, mu/physiology
- Recombinant Proteins/biosynthesis
- Signal Transduction
- Transfection/methods
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100
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Piros ET, Prather PL, Law PY, Evans CJ, Hales TG. Voltage-dependent inhibition of Ca2+ channels in GH3 cells by cloned mu- and delta-opioid receptors. Mol Pharmacol 1996; 50:947-56. [PMID: 8863841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
To study cloned opioid receptor binding and modulation of both adenylyl cyclase and ion channel activity, we stably expressed mu- and delta-opioid receptors in the rodent pituitary-derived GH3 cell line. GH3 cells express G proteins and voltage-activated Ca2+ channels (predominantly of the L-type). Activation of cloned rat mu-opioid receptors expressed in GH3 cells (termed GH3MOR cells) inhibits L-type Ca2+ channel activity. GH3MOR cells, further transfected with mouse delta receptor cDNA (termed GH3MORDOR cells), bound both [D-Ala2,N-MePhe4,Gly-ol5]enkephalin (DAMGO) and [D-Pen2,D-Pen5]enkephalin (DPDPE). These opioid ligands inhibited adenylyl cyclase activity (IC50 = 174 and 0.53 nM, respectively). This action of DAMGO and DPDPE was attenuated selectively by mu- and delta-opioid receptor-specific antagonists. Activation of both opioid receptors also led to inhibition of Ca2+ channel activity, measured with Ba2+ as the charge carrier using the whole-cell patch-clamp technique. Both DAMGO (1 microM) and DPDPE (1 microM) reversibly inhibited Ba2+ currents (by 17.0 +/- 1.4% and 20.7 +/- 1.3%, respectively) in GH3MORDOR cells. The inhibitory action of DPDPE was dose dependent (IC50 = 1.6 nM) and was attenuated by pretreatment with pertussis toxin (200 ng/ml) or by the inclusion of guanosine-5'-O-(2-thio)diphosphate (2 mM) in the recording electrode. Ba2+ current inhibitions by both DAMGO and DPDPE were completely reversed by depolarizing (to > 50 mV) prepulses in GH3MORDOR cells. In summary, cloned mu- and delta-opioid receptors expressed in GH3 cells voltage-dependently couple through Gi/G(o) proteins to L-type Ca2+ channels.
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MESH Headings
- Adenylate Cyclase Toxin
- Adenylyl Cyclase Inhibitors
- Adenylyl Cyclases/metabolism
- Animals
- Calcium Channel Blockers/pharmacology
- Calcium Channels/metabolism
- Calcium Channels/physiology
- Cell Line
- Cloning, Molecular
- Electrophysiology
- GTP-Binding Proteins/physiology
- Kinetics
- Pertussis Toxin
- Pituitary Gland/cytology
- Pituitary Gland/physiology
- Rats
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, delta/physiology
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Receptors, Opioid, mu/physiology
- Transfection
- Virulence Factors, Bordetella/pharmacology
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