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Min Zhu - One of the best experts on this subject based on the ideXlab platform.

  • application of Radioligand Receptor Binding assays in the search for the active principles of the traditional chinese medicine gouteng
    Phytotherapy Research, 1997
    Co-Authors: Min Zhu, Pamela M. Greengrass, J. D. Phillipson, N. G. Norman
    Abstract:

    Uncaria rhynchophylla and related species (i.e. Gouteng of the Pharmacopoeia of the People's Republic of China) have antihypertensive, sedative and anticonvulsant activities. A methanol extract of ‘Gouteng’ (U. rhynchopylla) hooks and stems was assessed for its ability to inhibit the Binding of Radioligands to 13 different Receptors in this study. The extract inhibited ligand-Receptor Binding by more than 60% to α2-adrenoceptors, dopamine 1, 5-HT1A, opiate, GABAA and GABAB Receptors. Bioassay-guided fractionation resulted in the isolation of ursolic acid (muscarinic and sulphonylureas activities), husutine (α2- and β-adrenoceptor, 5-HT1A and 2, opiate and sulphonylureas activities) and epiallocorynanthine (β-adrenoceptor, 5-HT1A and 2, and opiate Receptor activities). These findings are discussed in relation to the reported pharmacological properties, clinical uses and differing alkaloid profiles of those Uncaria species which constitute ‘Gouteng’ of the Pharmacopoeia of the People's Republic of China. © 1997 John Wiley & Sons, Ltd.

  • Application of Radioligand‐Receptor Binding assays in the search for the active principles of the traditional Chinese medicine ‘Gouteng’
    Phytotherapy Research, 1997
    Co-Authors: Min Zhu, Pamela M. Greengrass, J. D. Phillipson, N. G. Norman
    Abstract:

    Uncaria rhynchophylla and related species (i.e. Gouteng of the Pharmacopoeia of the People's Republic of China) have antihypertensive, sedative and anticonvulsant activities. A methanol extract of ‘Gouteng’ (U. rhynchopylla) hooks and stems was assessed for its ability to inhibit the Binding of Radioligands to 13 different Receptors in this study. The extract inhibited ligand-Receptor Binding by more than 60% to α2-adrenoceptors, dopamine 1, 5-HT1A, opiate, GABAA and GABAB Receptors. Bioassay-guided fractionation resulted in the isolation of ursolic acid (muscarinic and sulphonylureas activities), husutine (α2- and β-adrenoceptor, 5-HT1A and 2, opiate and sulphonylureas activities) and epiallocorynanthine (β-adrenoceptor, 5-HT1A and 2, and opiate Receptor activities). These findings are discussed in relation to the reported pharmacological properties, clinical uses and differing alkaloid profiles of those Uncaria species which constitute ‘Gouteng’ of the Pharmacopoeia of the People's Republic of China. © 1997 John Wiley & Sons, Ltd.

  • Application of Radioligand Receptor Binding assays in the search for CNS active principles from Chinese medicinal plants
    Journal of ethnopharmacology, 1996
    Co-Authors: Min Zhu, Norman G. Bowery, Pamela M. Greengrass, J. David Phillipson
    Abstract:

    Extracts of Schefflera bodinieri and S. delavayi (Araliaceae), Celastrus angulatus and C. orbiculatus (Celastraceae), Clerodendrum mandarinorum and C. bungei (Verbenaceae), Periploca callophylla and P. forrestii (Asclepiadaceae), Alangium platanifolium (Alangiaceae) and Uncaria rhynchophylla (Rubiaceae) were assessed for CNS activity against 18 Radioligand Receptor Binding assays. The Receptors used were alpha 1-, alpha 2- and beta-adrenoceptors, 5HT-1, 5HT-1A, 5HT-2, opiate, adenosine-1, benzodiazepine, Ca+2 channel, sulphonylureas, dopamine-1, dopamine-2, muscarinic, histamine-1, Na+/K+ ATPase, GABAA and GABAB. The results indicate that these ligand-Receptor Binding assays are useful for understanding the mode of action of herbal medicines and for bioassay guided fractionation of plant active ingredients.

  • Chemical and Biological Investigation of the Root Bark of Clerodendrum mandarinorum
    Planta medica, 1996
    Co-Authors: Min Zhu, J. D. Phillipson, Pam M. Greengrass, Norman G. Bowery
    Abstract:

    A 70% EtOH extract of Clerodendrum mandarinorum root bark was assessed for CNS activity against 18 Radioligand Receptor Binding assays. The results showed that the extract was able to bind to opiate, adenosine-1, alpha 2-adrenergic, 5HT-1, 5HT-2, dopamine-2, histamine-1, GABA(A), and GABA(B) Receptors. Fourteen compounds were isolated and identified by El-MS, 1H-NMR and 13C-NMR spectra as known triterpenoids (friedelanone, lupeol, betulinic acid), steroids (24S-stigmata-5,25-dien-3 beta-ol,22E,24S-stigmata-5,22,25-trien-3 beta-ol), flavonoids (cirsimaritin, cirsimaritin-4'-glucoside, quercetin-3-methyl ether), tetra-hydro-alpha-pyrone and saccharides (sucrose, alpha-D- and beta-D-glucopyranose, ethyl-alpha-D-glucopyranoside, 2-ethyl-beta-D-fructofuranoside). The isolated compounds were assessed for activity by the Radioligand Receptor Binding assays. Betulinic acid and ethyl-alpha-D-glucopyranoside showed weak activities against sulphonylureas (IC50 = 7.5 microM) and muscarinic Receptors (IC50 = 5.5 microM), respectively. Cirsimaritin-4'-glucoside was weakly active in the adenosine-1 Binding assay (IC50 = 3.0 microM), whereas seven structurally related flavonoids, not isolated from C.mandarinorum, were inactive.

Robert M. Weiss - One of the best experts on this subject based on the ideXlab platform.

  • Age Related Changes in the Functional, Biochemical and Molecular Properties of α1-Adrenoceptors in the Rat Genitourinary Tract
    The Journal of urology, 2006
    Co-Authors: Makoto Yono, Robert M. Weiss, Harris E. Foster, Jamshid Latifpour
    Abstract:

    Purpose: Because age related changes occur in the properties of α1-adrenoceptor in several mammalian tissues and α1-adrenoceptor antagonists are extensively used to treat lower urinary tract symptoms secondary to benign prostatic hyperplasia, we investigated age related changes in the functional, biochemical and molecular properties of α1-adrenoceptor in the rat genitourinary tract.Materials and Methods: The characteristics of α1-adrenoceptor in the ventral and dorsolateral prostate, and bladder base and dome of 3 and 22-month-old rats were determined using an isolated muscle bath, Radioligand Receptor Binding and real-time reverse transcriptase-polymerase chain reaction techniques.Results: Old rats had significantly higher body weight, lower testosterone, a smaller ventral prostate and a larger bladder dome than young rats. Although there was no significant age dependent difference in the properties of α1-adrenoceptor in the bladder base and dome, total α1-adrenoceptor density, mRNA expression of all 3 α...

  • Age-Related Changes in the Properties of the Endothelin Receptor System at Protein and mRNA Levels in the Rat Vas Deferens
    Journal of receptor and signal transduction research, 2004
    Co-Authors: Makoto Yono, Jamshid Latifpour, Wataru Takahashi, Mehdi Pouresmail, Parviz Afiatpour, Robert M. Weiss
    Abstract:

    As age-related changes occur in the properties of the endothelin (ET) Receptor system in several mammalian tissues, and as there are significant amounts of functional ET Receptors in the vas deferens, we investigated the age-related changes in the ET Receptor system at the protein and mRNA levels in the rat vas deferens. The ET system was investigated in the vasa deferentia of 3 weeks, 3 months and 22 months old rats. ET Receptors were characterized and quantified at the protein level by Radioligand Receptor Binding, and gene transcript levels of ET-1, ET-3, ET converting enzyme-1 (ECE-1), and ETA and ETB Receptor subtypes were quantified by real-time reverse transcription polymerase chain reaction (RT-PCR). The results of Radioligand Receptor Binding assays demonstrate that there is a higher density of total ET Receptors in the vas deferens of 3 weeks old rats than in 3 months and 22 months old rats, and that the predominant ET Receptor is of the ETA subtype in all three ages. Real-time RT-PCR data show ...

  • CHARACTERIZATION, LOCALIZATION AND DISTRIBUTION OF alpha1 ADRENOCEPTOR SUBTYPE IN MALE RABBIT URETHRA
    The Journal of urology, 1998
    Co-Authors: Kazuhiko Nishi, Jamshid Latifpour, Motoaki Saito, Harris E. Foster, Masaki Yoshida, Robert M. Weiss
    Abstract:

    AbstractPurpose: The subtype specificity, localization and distribution of urethral alpha1-adrenoceptors were studied in the male rabbit urethra.Materials and Methods: The properties of the urethral alpha1-adrenoceptors were investigated using Radioligand Receptor Binding and light microscopic autoradiography with [(125) I]iodo-2-[b-(4-hydroxyphenyl)-ethylaminomethyl]tetralone (HEAT), and immunohistochemistry with monoclonal anti-alpha smooth muscle actin and anti-alpha sarcomeric actin antibodies.Results: Saturation experiments with [(125) I]HEAT demonstrated the presence of significant amounts of a single high affinity Binding site for alpha1 adrenoceptors in the male rabbit urethra. The pharmacological profile of the alpha1 adrenoceptors in rabbit urethra, determined by inhibition experiments with subtype selective alpha1 adrenoceptor antagonists, was characterized by the following rank order of potency of inhibition constants (Ki values): prazosin

N. G. Norman - One of the best experts on this subject based on the ideXlab platform.

  • application of Radioligand Receptor Binding assays in the search for the active principles of the traditional chinese medicine gouteng
    Phytotherapy Research, 1997
    Co-Authors: Min Zhu, Pamela M. Greengrass, J. D. Phillipson, N. G. Norman
    Abstract:

    Uncaria rhynchophylla and related species (i.e. Gouteng of the Pharmacopoeia of the People's Republic of China) have antihypertensive, sedative and anticonvulsant activities. A methanol extract of ‘Gouteng’ (U. rhynchopylla) hooks and stems was assessed for its ability to inhibit the Binding of Radioligands to 13 different Receptors in this study. The extract inhibited ligand-Receptor Binding by more than 60% to α2-adrenoceptors, dopamine 1, 5-HT1A, opiate, GABAA and GABAB Receptors. Bioassay-guided fractionation resulted in the isolation of ursolic acid (muscarinic and sulphonylureas activities), husutine (α2- and β-adrenoceptor, 5-HT1A and 2, opiate and sulphonylureas activities) and epiallocorynanthine (β-adrenoceptor, 5-HT1A and 2, and opiate Receptor activities). These findings are discussed in relation to the reported pharmacological properties, clinical uses and differing alkaloid profiles of those Uncaria species which constitute ‘Gouteng’ of the Pharmacopoeia of the People's Republic of China. © 1997 John Wiley & Sons, Ltd.

  • Application of Radioligand‐Receptor Binding assays in the search for the active principles of the traditional Chinese medicine ‘Gouteng’
    Phytotherapy Research, 1997
    Co-Authors: Min Zhu, Pamela M. Greengrass, J. D. Phillipson, N. G. Norman
    Abstract:

    Uncaria rhynchophylla and related species (i.e. Gouteng of the Pharmacopoeia of the People's Republic of China) have antihypertensive, sedative and anticonvulsant activities. A methanol extract of ‘Gouteng’ (U. rhynchopylla) hooks and stems was assessed for its ability to inhibit the Binding of Radioligands to 13 different Receptors in this study. The extract inhibited ligand-Receptor Binding by more than 60% to α2-adrenoceptors, dopamine 1, 5-HT1A, opiate, GABAA and GABAB Receptors. Bioassay-guided fractionation resulted in the isolation of ursolic acid (muscarinic and sulphonylureas activities), husutine (α2- and β-adrenoceptor, 5-HT1A and 2, opiate and sulphonylureas activities) and epiallocorynanthine (β-adrenoceptor, 5-HT1A and 2, and opiate Receptor activities). These findings are discussed in relation to the reported pharmacological properties, clinical uses and differing alkaloid profiles of those Uncaria species which constitute ‘Gouteng’ of the Pharmacopoeia of the People's Republic of China. © 1997 John Wiley & Sons, Ltd.

Gregory M. Brown - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of [ 125I]iodomelatonin Binding sites in infant cerebellum of sudden infant death syndrome and non-sudden infant death syndrome
    Neuroscience letters, 1995
    Co-Authors: He Yuan, Camie W.y. Chan, William Q. Sturner, Shiu F. Pang, Gregory M. Brown
    Abstract:

    Abstract [125I]Iodomelatonin Binding sites in human infant cerebellum were studied by Radioligand Receptor Binding assay and in vitro quantitative autoradiography. The Binding sites characterized in membrane preparations revealed saturable, reversible and highly specific Binding sites with a Kd value of 21.2 ± 8.33 pM and a Bmax value of 2.02 ± 0.52 fmol/mg protein. 10 μM of GTPγS significantly reduced the Binding capacity, suggesting the possible G-protein coupling of the Binding sites. Autoradiographic study showed that the labelling was mainly located in the cerebellar cortex. On comparison of the Binding parameters from cerebellum of sudden infant death syndrome (SIDS) and non-SIDS infants, no significant change in Binding capacity and Binding affinity was detected. These findings suggest that the Binding sites in cerebellum may not be related to the etiology of SIDS.

Jamshid Latifpour - One of the best experts on this subject based on the ideXlab platform.

  • Age Related Changes in the Functional, Biochemical and Molecular Properties of α1-Adrenoceptors in the Rat Genitourinary Tract
    The Journal of urology, 2006
    Co-Authors: Makoto Yono, Robert M. Weiss, Harris E. Foster, Jamshid Latifpour
    Abstract:

    Purpose: Because age related changes occur in the properties of α1-adrenoceptor in several mammalian tissues and α1-adrenoceptor antagonists are extensively used to treat lower urinary tract symptoms secondary to benign prostatic hyperplasia, we investigated age related changes in the functional, biochemical and molecular properties of α1-adrenoceptor in the rat genitourinary tract.Materials and Methods: The characteristics of α1-adrenoceptor in the ventral and dorsolateral prostate, and bladder base and dome of 3 and 22-month-old rats were determined using an isolated muscle bath, Radioligand Receptor Binding and real-time reverse transcriptase-polymerase chain reaction techniques.Results: Old rats had significantly higher body weight, lower testosterone, a smaller ventral prostate and a larger bladder dome than young rats. Although there was no significant age dependent difference in the properties of α1-adrenoceptor in the bladder base and dome, total α1-adrenoceptor density, mRNA expression of all 3 α...

  • effects of chronic administration of doxazosin on α1 adrenoceptors in the rat prostate
    The Journal of Urology, 2004
    Co-Authors: Harris E. Foster, Makoto Yono, Wataru Takahashi, Mehdi Pouresmail, Parviz Afiatpour, David Shin, Jamshid Latifpour
    Abstract:

    ABSTRACTPurpose: Although the clinical efficacy of α1-adrenoceptor (α1-AR) antagonists for the treatment of benign prostatic hyperplasia is not disputed, their mechanism of action and ability to maintain long-term effectiveness have only recently been investigated. Since it is known that chronic administration of Receptor antagonists causes up-regulation in the targeted Receptor, we examined the effects of chronic administration of doxazosin, a nonspecific long acting α1-AR antagonist, on the properties of α1-AR subtypes in the rat prostate.Materials and Methods: Rats were treated with doxazosin (2 or 4 mg/kg daily subcutaneously, supplemented with 4 mg/kg daily orally) for 8 or 12 weeks. Prostatic α1-AR properties at the protein and gene transcript levels were quantified by Radioligand Receptor Binding and real-time reverse transcriptase-polymerase chain reaction, respectively.Results: Treated rats that received the highest levels of doxazosin had significantly heavier prostates compared with age matched...

  • Age-Related Changes in the Properties of the Endothelin Receptor System at Protein and mRNA Levels in the Rat Vas Deferens
    Journal of receptor and signal transduction research, 2004
    Co-Authors: Makoto Yono, Jamshid Latifpour, Wataru Takahashi, Mehdi Pouresmail, Parviz Afiatpour, Robert M. Weiss
    Abstract:

    As age-related changes occur in the properties of the endothelin (ET) Receptor system in several mammalian tissues, and as there are significant amounts of functional ET Receptors in the vas deferens, we investigated the age-related changes in the ET Receptor system at the protein and mRNA levels in the rat vas deferens. The ET system was investigated in the vasa deferentia of 3 weeks, 3 months and 22 months old rats. ET Receptors were characterized and quantified at the protein level by Radioligand Receptor Binding, and gene transcript levels of ET-1, ET-3, ET converting enzyme-1 (ECE-1), and ETA and ETB Receptor subtypes were quantified by real-time reverse transcription polymerase chain reaction (RT-PCR). The results of Radioligand Receptor Binding assays demonstrate that there is a higher density of total ET Receptors in the vas deferens of 3 weeks old rats than in 3 months and 22 months old rats, and that the predominant ET Receptor is of the ETA subtype in all three ages. Real-time RT-PCR data show ...

  • CHARACTERIZATION, LOCALIZATION AND DISTRIBUTION OF alpha1 ADRENOCEPTOR SUBTYPE IN MALE RABBIT URETHRA
    The Journal of urology, 1998
    Co-Authors: Kazuhiko Nishi, Jamshid Latifpour, Motoaki Saito, Harris E. Foster, Masaki Yoshida, Robert M. Weiss
    Abstract:

    AbstractPurpose: The subtype specificity, localization and distribution of urethral alpha1-adrenoceptors were studied in the male rabbit urethra.Materials and Methods: The properties of the urethral alpha1-adrenoceptors were investigated using Radioligand Receptor Binding and light microscopic autoradiography with [(125) I]iodo-2-[b-(4-hydroxyphenyl)-ethylaminomethyl]tetralone (HEAT), and immunohistochemistry with monoclonal anti-alpha smooth muscle actin and anti-alpha sarcomeric actin antibodies.Results: Saturation experiments with [(125) I]HEAT demonstrated the presence of significant amounts of a single high affinity Binding site for alpha1 adrenoceptors in the male rabbit urethra. The pharmacological profile of the alpha1 adrenoceptors in rabbit urethra, determined by inhibition experiments with subtype selective alpha1 adrenoceptor antagonists, was characterized by the following rank order of potency of inhibition constants (Ki values): prazosin