scholarly journals Glyoxalase (GLO1) inhibition or genetic overexpression does not alter ethanol’s locomotor effects: implications for GLO1 as a therapeutic target in alcohol use disorders

2017 ◽  
Author(s):  
Amanda M Barkley-Levenson ◽  
Frances A Lagarda ◽  
Abraham A Palmer
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Partial Agonist ◽  
Positive Control ◽  
Dose Response Curve ◽  
Locomotor Response ◽  
Over Expression ◽  
Locomotor Stimulation ◽  
Ethanol Drinking ◽  
The Brain

AbstractBackgroundGlyoxalase 1 (GLO1) is an enzyme that metabolizes methylglyoxal (MG), which is a competitive partial agonist at GABAA receptors. Inhibition of GLO1 increases concentrations of MG in the brain and decreases binge-like ethanol drinking. The present study assessed whether inhibition of GLO1, or genetic over expression of Glo1, would also alter the locomotor effects of ethanol, which might explain reduced ethanol consumption following GLO1 inhibition. We used the prototypical GABAA receptor agonist muscimol as a positive control.MethodsMale C57BL/6J mice were pretreated with aeither the GLO1 inhibitor S-bromobenzylglutathione cyclopentyl diester (pBBG; 7.5 mg/kg; Experiment 1) or muscimol (0.75 mg/kg; Experiment 2), or their corresponding vehicle. We then determined whether locomotor response to a range of ethanol doses (0, 0.5, 1.0, 1.5, 2.0, and 2.5) was altered by either pBBG or muscimol pretreatment. We also examined the locomotor response to a range of ethanol doses in FVB/NJ wild type and transgenic Glo1 over expressing mice (Experiment 3). Anxiety-like behavior (time spent in the center of the open field) was assessed in all three experiments.ResultsThe ethanol dose-response curve was not altered by pretreatment with pBBG or by transgenic overexpression of Glo1. In contrast, muscimol blunted locomotor stimulation at low ethanol doses, and potentiated locomotor sedation at higher ethanol doses. No drug or genotype differences were seen in anxiety-like behavior after ethanol treatment.ConclusionsThe dose of pBBG used in this study is within the effective range shown previously to reduce ethanol drinking. Glo1 overexpression has been previously shown to increase ethanol drinking. However, neither manipulation altered the dose response curve for ethanol’s locomotor effects, whereas muscimol appeared to enhance the locomotor sedative effects of ethanol. The present data demonstrate that reduced ethanol drinking caused by GLO1 inhibition is not due to potentiation of ethanol’s stimulant or depressant effects.

scholarly journals Synergistic effects of inositol 1,3,4,5-tetrakisphosphate on inositol 2,4,5-triphosphate-stimulated Ca2+ release do not involve direct interaction of inositol 1,3,4,5-tetrakisphosphate with inositol triphosphate-binding sites

1996 ◽  
Vol 314 (3) ◽  
pp. 811-816 ◽  
Author(s):  
Jeff W. LOOMIS-HUSSELBEE ◽  
Peter J. CULLEN ◽  
Uschi E. DREIKHAUSEN ◽  
Robin F. IRVINE ◽  
Alan P. DAWSON
Keyword(s):  
Dose Response ◽  
Binding Sites ◽  
Response Curve ◽  
Partial Agonist ◽  
Synergistic Effects ◽  
Direct Interaction ◽  
Dose Response Curve ◽  
Slow Phase ◽  
L1210 Cells ◽  
Insp3 Receptor

We have previously found that for permeabilized L1210 cells, low micromolar concentrations of Ins(1,3,4,5)P4 added prior to Ins(2,4,5)P3 enhance the effects of suboptimal concentrations of Ins(2,4,5)P3 in causing Ca2+ release from InsP3-sensitive Ca2+ stores [Cullen, Irvine and Dawson (1990) Biochem. J. 271, 549–553]. If this was due either to some conversion of added Ins(1,3,4,5)P4 into Ins(1,4,5)P3 by the 3-phosphatase, or to Ins(1,3,4,5)P4 acting as a weak (or partial) agonist on the InsP3 receptor it would be expected that, in the presence of thimerosal to sensitize the InsP3 receptor, the dose–response curve to Ins(1,3,4,5)P4 would be left-shifted by the same extent as that of Ins(1,4,5)P3. This was found not to be the case; the dose–response curve to Ins(1,3,4,5)P4 was not shifted at all by thimerosal. Furthermore, L-Ins(1,3,4,5)P4, which can displace radiolabelled D-Ins(1,3,4,5)P4 but not D-Ins(1,4,5)P3 from their respective high-affinity binding sites, mimicked the effects of D-Ins(1,3,4,5)P4 in enhancing the slow phase of Ins(2,4,5)P3-stimulated Ca2+ release. Ins(1,3,4,5)P4 caused an increase in magnitude of the slow phase of InsP3-stimulated Ca2+ release leaving the magnitude of the fast phase unaltered, in contrast to increasing Ins(2,4,5)P3 concentrations which increased the size of both phases. In addition, Ins(1,3,4,5)P4 decreased the rate constant for the slow phase of Ca2+ release These findings point strongly to the conclusion that InsP4 is not working directly via the InsP3 receptor but indirectly via an InsP4 receptor.

scholarly journals Properties of the Glucocorticoid Modulatory Element Binding Proteins GMEB-1 and -2: Potential New Modifiers of Glucocorticoid Receptor Transactivation and Members of the Family of KDWK Proteins

2000 ◽  
Vol 14 (7) ◽  
pp. 1010-1027 ◽  
Author(s):  
Sunil Kaul ◽  
John A. Blackford ◽  
Jun Chen ◽  
Vasily V. Ogryzko ◽  
S. Stoney Simons
Keyword(s):  
Glucocorticoid Receptor ◽  
Dose Response ◽  
Response Curve ◽  
Partial Agonist ◽  
Dose Response Curve ◽  
Limiting Factors ◽  
Creb Binding Protein ◽  
Agonist Activity ◽  
Histone Acetyl Transferase ◽  
Two Hybrid

Abstract An important component of glucocorticoid steroid induction of tyrosine aminotransferase (TAT) gene expression is the glucocorticoid modulatory element (GME), which is located at −3.6 kb of the rat TAT gene. The GME both mediates a greater sensitivity to hormone, due to a left shift in the dose-response curve of agonists, and increases the partial agonist activity of antiglucocorticoids. These properties of the GME are intimately related to the binding of a heteromeric complex of two proteins (GMEB-1 and -2). We previously cloned the rat GMEB-2 as a 67-kDa protein. We now report the cloning of the other member of the GME binding complex, the 88-kDa human GMEB-1, and various properties of both proteins. GMEB-1 and -2 each possess an intrinsic transactivation activity in mammalian one-hybrid assays, consistent with our proposed model in which they modify glucocorticoid receptor (GR)-regulated gene induction. This hypothesis is supported by interactions between GR and both GMEB-1 and -2 in mammalian two-hybrid and in pull-down assays. Furthermore, overexpression of GMEB-1 and -2, either alone or in combination, results in a reversible right shift in the dose-response curve, and decreased agonist activity of antisteroids, as expected from the squelching of other limiting factors. Additional mechanistic details that are compatible with the model of GME action are suggested by the interactions in a two-hybrid assay of both GMEBs with CREB-binding protein (CBP) and the absence of histone acetyl transferase (HAT) activity in both proteins. GMEB-1 and -2 share a sequence of 90 amino acids that is 80% identical. This region also displays homology to several other proteins containing a core sequence of KDWK. Thus, the GMEBs may be members of a new family of factors with interesting transcriptional properties.

A theory of drug action based on the rate of drug-receptor combination

1961 ◽  
Vol 154 (954) ◽  
pp. 21-69 ◽  
Keyword(s):  
Rate Constant ◽  
Dose Response ◽  
Response Curve ◽  
Time Course ◽  
Partial Agonist ◽  
Drug Action ◽  
Dose Response Curve ◽  
Rate Theory ◽  
Response Curves ◽  
Drug Receptor

A theory of drug action is developed on the assumption that excitation by a stimulant drug is proportional to the rate of drug-receptor combination, rather than to the proportion of receptors occupied by the drug. The properties of a drug can then be specified by two rate constants: k 1 , the association rate constant, and k 2 , the dissociation rate constant; the ratio k 2 / k 1 ═ k e corresponds to the reciprocal of the ‘affinity’. The value of k e then determines potency, and k 2 determines whether the drug is a powerful stimulant ( k 2 high), a partial agonist with ability both to excite and to antagonize ( k 2 moderate) or an antagonist with vestiges of stimulant action ( k 2 low). Qualitatively such a theory accounts for the persistence of effect of an antagonist on a tissue; for the characteristic sequence of excitation followed by block with drugs such as nicotine; for certain forms of tachyphylaxis; and for the vestiges of stimulant action possessed by classical antagonists. The theory has been tested on the guinea-pig ileum with acetylcholine and histamine as agonists, hyoscine, mepyramine and atropine as antagonists and alkyltrimethylammonium compounds as partial agonists, and it was corroborated in the following respects: 1. The dose-response curve of acetylcholine or histamine has the predicted form, if it is determined with an auxotonic rather than with an isotonic lever. 2. The rates of offset and of onset of antagonism, expressed in terms of change of receptor occupation by the antagonist, follow an exponential course from which k 1 and k 2 can be measured. Values of k 2 / k 1 so obtained agree with those obtained from the intensity of antagonism at equilibrium. The rate of onset of action increases in proportion to the antagonistic dose ratio finally achieved. The rate of offset of action is independent of the intensity of the antagonism or of the time taken to achieve it, up to dose ratios of 20 to 100. Diffusion barriers do not appear to contribute significantly to the time course of action of drugs such as hyoscine or mepyramine except at high dosage. 3. With the alkyltrimethylammonium compounds (hexyl to dodecyl): ( a ) the rate of onset and offset of antagonistic action fell with increasing potency. ( b ) The excitation produced always reached a peak response soon after injection which faded thereafter to a lower equilibrium value, with a time constant comparable with that predicted from the atropinic action. The rate and proportion of fade increased with dose. The dose-response curve for peak responses is bell-shaped, but not that for equilibrium responses. ( c ) The slope of the foot of the dose-response curves of the series and the magnitude of the maximum equilibrium responses correlated with the estimates of k 1 and k 2 , respectively, obtained from analysis of the atropinic action. The alkyltrimethylammonium compounds could be specified by a k 1 which is constant and a k 2 diminishing by a factor of about 2∙5 for each methylene group added. It is suggested that association is determined by the cationic head, and dissociation by shorter-range binding forces. 4. The responses to strong stimulants, such as histamine or acetylcholine, cannot be fully described in these terms. Following exposure to them the ileum is non-specifically desensitized. This desensitization is detectable with small doses, increases with dose and duration of exposure, and differs in its course to recovery from a specific antagonism. 5. A similar desensitization follows the removal of potassium from the fluid in which the ileum is immersed, and the two forms of desensitization summate. If potassium-free solution is applied rapidly, a contraction of the ileum occurs, indistinguishable from that due to acetylcholine. It is suggested as a working hypothesis of stimulant action that the drug ion exchanges with potassium at the receptor, and is then released from the receptor in exchange for potassium derived intracellularly, so that the chemoceptive action involves an extraction of potassium from the tissue. The implications of rate theory and of non-specific desensitization for theories of drug action are discussed.

scholarly journals Modulation of Induction Properties of Glucocorticoid Receptor-Agonist and -Antagonist Complexes by Coactivators Involves Binding to Receptors but Is Independent of Ability of Coactivators to Augment Transactivation

2002 ◽  
Vol 277 (51) ◽  
pp. 49256-49266 ◽  
Author(s):  
Yuanzheng He ◽  
Daniele Szapary ◽  
S. Stoney Simons
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Glucocorticoid Receptors ◽  
Partial Agonist ◽  
Dose Response Curve ◽  
Receptor Interaction ◽  
Agonist Activity ◽  
Partial Agonist Activity ◽  
Agonist And Antagonist ◽  
Two Hybrid

Coactivators such as TIF2 and SRC-1 modulate the positioning of the dose-response curve for agonist-bound glucocorticoid receptors (GRs) and the partial agonist activity of antiglucocorticoid complexes. These properties of coactivators differ from their initially defined activities of binding to, and increasing the total levels of transactivation by, agonist-bound steroid receptors. We now report that constructs of TIF2 and SRC-1 lacking the two activation domains (AD1 and AD2) have significantly less ability to increase transactivation but retain most of the activity for modulating the dose-response curve and partial agonist activity. Mammalian two-hybrid experiments show that the minimum TIF2 segment with modulatory activity (TIF2.4) does not interact with p300, CREB-binding protein, or PCAF, which also modulates GR activities. DRIP150 and DRIP205 have been implicated in coactivator actions but are unable to modulate GR activities. The absence of synergism by PCAF or DRIP150 with SRC-1 or TIF2, respectively, further suggests that these other factors are not involved. The ability of a TIF2.4 fragment (i.e.TIF2.37), which is not known to interact with proteins, to block the actions of TIF2.4 suggests that an unidentified binder mediates the modulatory activity of TIF2. Pull-down experiments with GST/TIF2.4 demonstrate a direct interaction of TIF2 with GR in a hormone-dependent fashion that requires the receptor interaction domains of TIF2 and is equally robust with agonists and most antiglucocorticoids. These observations, which are confirmed in mammalian two-hybrid assays, suggest that the capacity of coactivators such as TIF2 to modulate the partial agonist activity of antisteroids is mediated by the binding of coactivators to GR-antagonist complexes. In conclusion, the modulatory activity of coactivators with GR-agonist and -antagonist complexes is mechanistically distinct from the ability of coactivators to augment the total levels of transactivation and appears to involve the binding to both GR-steroid complexes and an unidentified TIF2-associated factor(s).

OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1967 ◽  
Vol 56 (4) ◽  
pp. 619-625 ◽  
Author(s):  
Hans Jacob Koed ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Origin ◽  
Response Curves ◽  
Significant Difference ◽  
The Mean ◽  
Different Levels

ABSTRACT Comparison of the dose-response curves for LH of ovine origin (NIH-LH-S8) and of human origin (IRP-HMG-2) using the OAAD test showed a small, though statistically significant difference, the dose-response curve for LH of human origin being a little flatter. Two standard curves for ovine LH obtained with 14 months' interval, were parallel but at different levels of ovarian ascorbic acid. When the mean ascorbic acid depletions were calculated as percentages of the control levels, the two curves for NIH-LH-S8 were identical. The use of standards of human origin in the OAAD test for LH activity of human preparations is recommended.

HYPERTROPHIC ADRENALS AND THEIR RESPONSE TO STRESS AFTER LESIONS IN THE MEDIAN EMINENCE OF TOTALLY HYPOPHYSECTOMIZED PIGEONS

1961 ◽  
Vol 37 (4) ◽  
pp. 565-576 ◽  
Author(s):  
Richard A. Miller
Keyword(s):  
Dose Response ◽  
Median Eminence ◽  
Response Curve ◽  
Liver Parenchyma ◽  
Dose Response Curve ◽  
Pars Distalis ◽  
Adrenal Enlargement ◽  
Response To Stress ◽  
Lethal Doses ◽  
Chromaffin Tissue

ABSTRACT Four per cent formaldehyde, insulin, or epinephrine in oil was injected for 5 days into pigeons subjected to varying degrees of hypophysectomy alone or together with large lesions in the median eminence and hypothalamus. Adrenals atrophied after the removal of the pars distalis alone or together with the neurohypophysis in untreated pigeons but showed markedly hypertrophic interrenal tissue (cortex in mammals) after treatment with formaldehyde or insulin. The slope of the dose-response curve was similar in operated and unoperated pigeons. The accumulation of bile in the liver parenchyma, which may occur after removal of the pars distalis, is an endogenous stress which was associated regularly with adrenal hypertrophy. After very large lesions of the median eminence and ventral hypothalamus in addition to total hypophysectomy, adrenals hypertrophied rather than atrophied, and the response to formaldehyde paralleled that in intact and »hypohysectomized« pigeons. Interrenal tissue was stimulated regularly; chromaffin tissue was partially degranulated, sometimes showed hyperplasia with colchicine, but only occasionally appeared hypertrophied. Epinephrine in nearly lethal doses caused only minimal adrenal enlargement. After adrenal denervation followed by hypophysectomy, the adrenals were still stimulated by formaldehyde. It appears that the interrenal tissue of the pigeon responds to a humoral stimulus not of hypophyseal origin in the absence of the hypophyseal-hypothalamic system.

ANTI-OVULATORY ACTIVITY OF STEROIDS ADMINISTERED BY GAVAGE IN THE ADULT OESTRUS RABBIT

1963 ◽  
Vol 42 (2_Suppl) ◽  
pp. S17-S30
Author(s):  
Fred A. Kind ◽  
Ralph I. Dorfman
Keyword(s):  
Dose Response ◽  
Active Compound ◽  
Subcutaneous Injection ◽  
Response Curve ◽  
Parent Compound ◽  
Dose Response Curve ◽  
Relative Potency ◽  
Reference Standard ◽  
Highly Active ◽  
Dose Levels

ABSTRACT Thirty-seven steroids have been studied as orally effective inhibitors of ovulation in the mated oestrus rabbit. Norethisterone served as the reference standard and a dose response curve was established between the 0.31 and 1.25 mg dose levels. Nine highly active anti-ovulatory compounds are described listed in a decreasing order of potency with norethisterone having the arbitrary value of one: 6-chloro-Δ6-dehydro-17α-acetoxyprogesterone (35), 6α-methyl-Δ1-dehydro-17α-acetoxyprogesterone (≥ 10), 6-fluoro-Δ6-dehydro-17α-acetoxyprogesterone(9), 6-methyl-Δ6-dehydro-17α-acetoxyprogesterone (5), Δ6-dehydro-17α-acetoxyprogesterone (≥ 3), 6α-methyl-17α-acetoxyprogesterone (2.6), 6-chloro-Δ1,6-bisdehydro-17α-acetoxyprogesterone (≥ 2), 2-hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one (≥ 2), and 6α-fluoro-16α-methyl-17α-acetoxyprogesterone (≥ 1.25). The anti-ovulatory activity of a compound was not related necessarily to the progestational activity of a compound nor to the anti-gonadotrophic activity as measured in parabiotic rats. 6-Chloro-Δ60dehydro-17-acetoxyprogesterone was as effective by gavage as previously shown by subcutaneous injection. 2-Hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one was at least 2.5 times more active by gavage than by injection. While 17α-acetoxyprogesterone was a very weak anti-ovulatory steroid, modifications of the structure by addition of methyl or halogen at the 6α position with or without unsaturation greatly increased the activity. 6-Chloro-Δ6-dehydro-27α-acetoxyprogesterone was the most active compound in this series showing a relative potency of 3500 times that of the parent compound 17α-acetoxyprogesterone.

scholarly journals Enhancement of morphine-induced antinociception after electroconvulsive shock in mice

2021 ◽  
Vol 17 ◽  
pp. 174480692199262
Author(s):  
Ken Iwata ◽  
Yukio Takamatsu ◽  
Nagafumi Doi ◽  
Kazutaka Ikeda
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Antinociceptive Effect ◽  
Dose Response Curve ◽  
Expression Level ◽  
Morphine Injection ◽  
Hot Plate ◽  
Hot Plate Test ◽  
Plate Test ◽  
Pain Patients

Electroconvulsive therapy (ECT) has been applied for chronic pain for decades. The amounts of opioids to treat pain are sometimes reduced after a series of ECT. The effect of ECT on morphine-induced analgesia and its mechanism underlying the reduction of morphine requirement has yet to be clarified. Therefore, we administered electroconvulsive shocks (ECS) to mice and investigated the antinociceptive effect of morphine in a hot plate test. We examined the expression level of µ-opioid receptor in the thalami of mice 25 h after administration of ECS compared to the thalami of mice without ECS administration using western blotting. ECS disturbed the development of a decrease in the percentage of maximal possible effect (%MPE), which was observed 24 h after a morphine injection, when ECS was applied 25, 23, 21, and 12 h before the second administration of morphine. We also examined the effect of ECS on the dose-response curve of %MPE to morphine-antinociception. Twenty-five hours after ECS, the dose-response curve was shifted to the left, and the EC50 of morphine given to ECS-pretreated mice decreased by 30.1% compared to the mice that were not pretreated with ECS. We also found that the expression level of µ-opioid receptors was significantly increased after ECS administration. These results confirm previous clinical reports showing that ECT decreased the required dose of opioids in neuropathic pain patients and suggest the hypothesis that this effect of ECT works through the thalamus.

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