The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform

Toyokazu Hiranuma - One of the best experts on this subject based on the ideXlab platform.

  • protection against dynorphin 1 8 hydrolysis in membrane preparations by the combination of amastatin captopril and phosphoramidon
    Journal of Pharmacology and Experimental Therapeutics, 1998
    Co-Authors: Toyokazu Hiranuma, Masayuki Kanai, Yoshiharu Arai, Ken Kitamura, Takao Taniguchi, Kayoko Iwao
    Abstract:

    The amounts of dynorphin-(1–8) [dyn-(1–8)] and its seven hydrolysis products, Y, YG, YGG, YGGF, YGGFL, YGGFLR and YGGFLRR, were estimated after incubating dyn-(1–8) with a membrane fraction from either guinea-pig ileum or striatum for various times at 37°C. The major hydrolysis products during the initial 5-min incubation were YGGFLR and Y, which indicates that Dipeptidyl Carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. After 60 min of incubation, dyn-(1–8) was completely hydrolyzed in both membrane preparations. When the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a Dipeptidyl Carboxypeptidase Inhibitor, and amastatin, an aminopeptidase Inhibitor, 63.8 and 49.3% of dyn-(1–8), respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with dyn-(1–8) in the presence of three peptidase Inhibitors, captopril, amastatin and phosphoramidon (an Inhibitor of endopeptidase-24.11), approximately 95% of the opioid octapeptide remained intact in both cases. This shows that dyn-(1–8) was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive Dipeptidyl Carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. Additionally, the Ke (equilibrium dissociation constant) values of selective antagonists against dyn-(1–8) and its initial main hydrolysis product YGGFLR in two isolated preparations pretreated with the three peptidase Inhibitors indicate that the latter acts on mu receptors in guinea pig ileum but delta receptors in mouse vas deferens and the former acts on kappa receptors in both preparations. It is indicated, therefore, that in the absence of peptidase Inhibitors endogenously released dyn-(1–8) acts either through dyn-(1–8) itself on kappa receptors or through YGGFLR on mu or delta receptors depending on both the three peptidase activities and the three receptor type densities at the target synaptic membrane.

  • almost complete protection from met5 enkephalin arg6 gly7 leu8 met enk rgl hydrolysis in membrane preparations by the combination of amastatin captopril and phosphoramidon
    Journal of Pharmacology and Experimental Therapeutics, 1997
    Co-Authors: Toyokazu Hiranuma, Kayoko Iwao, Ken Kitamura, Teruhiko Matsumiya
    Abstract:

    The contents of [Met5]-enkephalin-Arg6-Gly7-Leu8(met-enk-RGL) and its seven hydrolysis products—Y, YG, YGG, YGGF, YGGFM, YGGFMR, and YGGFMRG—were estimated after incubating met-enk-RGL with a membrane fraction from either guinea pig ileum or striatum for various times at 37°C. After 15 min of incubation, met-enk-RGL was completely hydrolyzed in both the ileal and the striatal membrane preparations. The major hydrolysis products were YGGFMR, YGGF and Y, which indicates that Dipeptidyl Carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. Additionally, even when the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a Dipeptidyl Carboxypeptidase Inhibitor, and amastatin, an aminopeptidase Inhibitor, 24% and 44% of enkephalin octapeptide, respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with met-enk-RGL in the presence of three peptidase Inhibitors—captopril, amastatin, and phosphoramidon (an Inhibitor of endopeptidase-24.11)—approximately 95% of the enkephalin octapeptide, remained intact in both cases. This shows that met-enk-RGL was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive Dipeptidyl Carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. We also reported the potencies of several opioids relative to that of met-enk-RGL in guinea pig ileum pretreated with the three peptidase Inhibitors.

Teruhiko Matsumiya - One of the best experts on this subject based on the ideXlab platform.

  • almost complete protection from met5 enkephalin arg6 gly7 leu8 met enk rgl hydrolysis in membrane preparations by the combination of amastatin captopril and phosphoramidon
    Journal of Pharmacology and Experimental Therapeutics, 1997
    Co-Authors: Toyokazu Hiranuma, Kayoko Iwao, Ken Kitamura, Teruhiko Matsumiya
    Abstract:

    The contents of [Met5]-enkephalin-Arg6-Gly7-Leu8(met-enk-RGL) and its seven hydrolysis products—Y, YG, YGG, YGGF, YGGFM, YGGFMR, and YGGFMRG—were estimated after incubating met-enk-RGL with a membrane fraction from either guinea pig ileum or striatum for various times at 37°C. After 15 min of incubation, met-enk-RGL was completely hydrolyzed in both the ileal and the striatal membrane preparations. The major hydrolysis products were YGGFMR, YGGF and Y, which indicates that Dipeptidyl Carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. Additionally, even when the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a Dipeptidyl Carboxypeptidase Inhibitor, and amastatin, an aminopeptidase Inhibitor, 24% and 44% of enkephalin octapeptide, respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with met-enk-RGL in the presence of three peptidase Inhibitors—captopril, amastatin, and phosphoramidon (an Inhibitor of endopeptidase-24.11)—approximately 95% of the enkephalin octapeptide, remained intact in both cases. This shows that met-enk-RGL was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive Dipeptidyl Carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. We also reported the potencies of several opioids relative to that of met-enk-RGL in guinea pig ileum pretreated with the three peptidase Inhibitors.

Kayoko Iwao - One of the best experts on this subject based on the ideXlab platform.

  • protection against dynorphin 1 8 hydrolysis in membrane preparations by the combination of amastatin captopril and phosphoramidon
    Journal of Pharmacology and Experimental Therapeutics, 1998
    Co-Authors: Toyokazu Hiranuma, Masayuki Kanai, Yoshiharu Arai, Ken Kitamura, Takao Taniguchi, Kayoko Iwao
    Abstract:

    The amounts of dynorphin-(1–8) [dyn-(1–8)] and its seven hydrolysis products, Y, YG, YGG, YGGF, YGGFL, YGGFLR and YGGFLRR, were estimated after incubating dyn-(1–8) with a membrane fraction from either guinea-pig ileum or striatum for various times at 37°C. The major hydrolysis products during the initial 5-min incubation were YGGFLR and Y, which indicates that Dipeptidyl Carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. After 60 min of incubation, dyn-(1–8) was completely hydrolyzed in both membrane preparations. When the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a Dipeptidyl Carboxypeptidase Inhibitor, and amastatin, an aminopeptidase Inhibitor, 63.8 and 49.3% of dyn-(1–8), respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with dyn-(1–8) in the presence of three peptidase Inhibitors, captopril, amastatin and phosphoramidon (an Inhibitor of endopeptidase-24.11), approximately 95% of the opioid octapeptide remained intact in both cases. This shows that dyn-(1–8) was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive Dipeptidyl Carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. Additionally, the Ke (equilibrium dissociation constant) values of selective antagonists against dyn-(1–8) and its initial main hydrolysis product YGGFLR in two isolated preparations pretreated with the three peptidase Inhibitors indicate that the latter acts on mu receptors in guinea pig ileum but delta receptors in mouse vas deferens and the former acts on kappa receptors in both preparations. It is indicated, therefore, that in the absence of peptidase Inhibitors endogenously released dyn-(1–8) acts either through dyn-(1–8) itself on kappa receptors or through YGGFLR on mu or delta receptors depending on both the three peptidase activities and the three receptor type densities at the target synaptic membrane.

  • almost complete protection from met5 enkephalin arg6 gly7 leu8 met enk rgl hydrolysis in membrane preparations by the combination of amastatin captopril and phosphoramidon
    Journal of Pharmacology and Experimental Therapeutics, 1997
    Co-Authors: Toyokazu Hiranuma, Kayoko Iwao, Ken Kitamura, Teruhiko Matsumiya
    Abstract:

    The contents of [Met5]-enkephalin-Arg6-Gly7-Leu8(met-enk-RGL) and its seven hydrolysis products—Y, YG, YGG, YGGF, YGGFM, YGGFMR, and YGGFMRG—were estimated after incubating met-enk-RGL with a membrane fraction from either guinea pig ileum or striatum for various times at 37°C. After 15 min of incubation, met-enk-RGL was completely hydrolyzed in both the ileal and the striatal membrane preparations. The major hydrolysis products were YGGFMR, YGGF and Y, which indicates that Dipeptidyl Carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. Additionally, even when the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a Dipeptidyl Carboxypeptidase Inhibitor, and amastatin, an aminopeptidase Inhibitor, 24% and 44% of enkephalin octapeptide, respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with met-enk-RGL in the presence of three peptidase Inhibitors—captopril, amastatin, and phosphoramidon (an Inhibitor of endopeptidase-24.11)—approximately 95% of the enkephalin octapeptide, remained intact in both cases. This shows that met-enk-RGL was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive Dipeptidyl Carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. We also reported the potencies of several opioids relative to that of met-enk-RGL in guinea pig ileum pretreated with the three peptidase Inhibitors.

Roy G. Goldie - One of the best experts on this subject based on the ideXlab platform.

  • Quantitative assessment of increased airway microvascular permeability to 125I-labelled plasma fibrinogen induced by platelet activating factor and bradykinin.
    British journal of pharmacology, 1991
    Co-Authors: K.e. Pedersen, Paul Rigby, Roy G. Goldie
    Abstract:

    1. We have used 125I-labelled fibrinogen (I-FN) in experiments monitoring plasma extravasation from vessels within guinea-pig trachea and peripheral lung tissue in response to platelet activating factor (PAF) and bradykinin (BK). Retained tissue radioactivity derived from I-FN was detected by direct measurement and by autoradiography. 2. Both PAF and BK caused concentration-dependent increases in radioactivity in trachea and peripheral lung, with PAF being approximately 1000 times more potent than BK at both sites. On a wet weight basis, mean tracheal leakage responses to PAF and BK were approximately 6 times and 2 times greater respectively than those in peripheral lung. Furthermore, in trachea, the maximal response to PAF was nearly twice that to BK, although they were approximately equiactive in peripheral lung. The Dipeptidyl Carboxypeptidase Inhibitor, enalapril (1 mg kg-1, i.v.), increased the potency of BK by approximately 40 fold. 3. In trachea, PAF (50 ng kg-1, i.v.)-induced leakage was selectively inhibited by the PAF receptor antagonist, WEB 2086 (5-50 micrograms kg-1), while responses to BK (50 micrograms kg-1, i.v.) were selectively inhibited by the BK2 receptor antagonist NPC 349 (0.5-1 mg kg-1). Neither PAF nor BK-induced leakage were significantly altered by pretreatment with the histamine H1-receptor antagonists mepyramine (10 micrograms kg-1) or ketotifen (50 micrograms kg-1) or the leukotriene receptor antagonist SKF 104353. These data indicate that both agonists caused direct, specific receptor operated increases in tracheal vascular permeability to plasma macromolecules.The alpha/beta1-adrenoceptor agonist adrenaline (100 pgkg-1) caused modest inhibition of leakage induced by BK, but not of the leakage response to PAF.4. Peripheral airway leakage responses to both PAF and BK were also detected by light microscopic autoradiography in paraffin-embedded tissue sections. This was possible since a significant amount of extravasated I-FN was apparently precipitated and fixed in the extravascular space as 125-labelled fibrin. Autoradiograms showed that both agonists caused increases in peripheral bronchial circulation microvascular permeability to I-FN. No evidence for leakage in alveolar wall capillaries or in pulmonary blood vessels was observed. Quantitation of such autoradiographic data will allow a comprehensive evaluation of the effects of putative asthma mediators on microvascular permeability throughout the respiratory tree.

Ken Kitamura - One of the best experts on this subject based on the ideXlab platform.

  • protection against dynorphin 1 8 hydrolysis in membrane preparations by the combination of amastatin captopril and phosphoramidon
    Journal of Pharmacology and Experimental Therapeutics, 1998
    Co-Authors: Toyokazu Hiranuma, Masayuki Kanai, Yoshiharu Arai, Ken Kitamura, Takao Taniguchi, Kayoko Iwao
    Abstract:

    The amounts of dynorphin-(1–8) [dyn-(1–8)] and its seven hydrolysis products, Y, YG, YGG, YGGF, YGGFL, YGGFLR and YGGFLRR, were estimated after incubating dyn-(1–8) with a membrane fraction from either guinea-pig ileum or striatum for various times at 37°C. The major hydrolysis products during the initial 5-min incubation were YGGFLR and Y, which indicates that Dipeptidyl Carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. After 60 min of incubation, dyn-(1–8) was completely hydrolyzed in both membrane preparations. When the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a Dipeptidyl Carboxypeptidase Inhibitor, and amastatin, an aminopeptidase Inhibitor, 63.8 and 49.3% of dyn-(1–8), respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with dyn-(1–8) in the presence of three peptidase Inhibitors, captopril, amastatin and phosphoramidon (an Inhibitor of endopeptidase-24.11), approximately 95% of the opioid octapeptide remained intact in both cases. This shows that dyn-(1–8) was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive Dipeptidyl Carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. Additionally, the Ke (equilibrium dissociation constant) values of selective antagonists against dyn-(1–8) and its initial main hydrolysis product YGGFLR in two isolated preparations pretreated with the three peptidase Inhibitors indicate that the latter acts on mu receptors in guinea pig ileum but delta receptors in mouse vas deferens and the former acts on kappa receptors in both preparations. It is indicated, therefore, that in the absence of peptidase Inhibitors endogenously released dyn-(1–8) acts either through dyn-(1–8) itself on kappa receptors or through YGGFLR on mu or delta receptors depending on both the three peptidase activities and the three receptor type densities at the target synaptic membrane.

  • almost complete protection from met5 enkephalin arg6 gly7 leu8 met enk rgl hydrolysis in membrane preparations by the combination of amastatin captopril and phosphoramidon
    Journal of Pharmacology and Experimental Therapeutics, 1997
    Co-Authors: Toyokazu Hiranuma, Kayoko Iwao, Ken Kitamura, Teruhiko Matsumiya
    Abstract:

    The contents of [Met5]-enkephalin-Arg6-Gly7-Leu8(met-enk-RGL) and its seven hydrolysis products—Y, YG, YGG, YGGF, YGGFM, YGGFMR, and YGGFMRG—were estimated after incubating met-enk-RGL with a membrane fraction from either guinea pig ileum or striatum for various times at 37°C. After 15 min of incubation, met-enk-RGL was completely hydrolyzed in both the ileal and the striatal membrane preparations. The major hydrolysis products were YGGFMR, YGGF and Y, which indicates that Dipeptidyl Carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. Additionally, even when the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a Dipeptidyl Carboxypeptidase Inhibitor, and amastatin, an aminopeptidase Inhibitor, 24% and 44% of enkephalin octapeptide, respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with met-enk-RGL in the presence of three peptidase Inhibitors—captopril, amastatin, and phosphoramidon (an Inhibitor of endopeptidase-24.11)—approximately 95% of the enkephalin octapeptide, remained intact in both cases. This shows that met-enk-RGL was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive Dipeptidyl Carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. We also reported the potencies of several opioids relative to that of met-enk-RGL in guinea pig ileum pretreated with the three peptidase Inhibitors.