7-Chlorokynurenic acid is a selective antagonist at the glycine modulatory site of the N-methyl-D-aspartate receptor complex (original) (raw)
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The Journal of physiology, 1990
1. Kynurenate (Kyn), 7-chlorokynurenate (7-Cl-Kyn), 3-amino-1-hydroxypyrrolid-2-one (HA-966) and D-cycloserine are known to bind to the glycine site that modulates the N-methyl-D-aspartate (NMDA) response of vertebrate central neurones. The effects of these compounds were investigated with patch-clamp and fast-perfusion techniques on mouse cortical neurones in primary culture in an effort to establish whether they act as antagonists, partial agonists and/or inverse agonists of glycine. A fast drug application method allowed the study of both steady-state and transient responses. 2. The analysis of steady-state responses indicates that the main effects of Kyn and 7-Cl-Kyn are those expected from competitive antagonists of glycine, with a dissociation constant of 15 microM for Kyn, and of 0.3 microM for 7-Cl-Kyn. Concentration jumps indicate that at all concentrations of glycine, and in particular in the absence of added glycine, the blockade by Kyn and 7-Cl-Kyn develops at a rate whi...
Journal of Neurochemistry, 1989
I -Aminocyclopropane carboxylic acid (ACPC) competitively inhibited (IC5", 38 * 7 nM) ['Hlglycine binding to rat forebrain membranes but did not affect ['Hlstrychnine binding to rat brainstem/ spinal cord membranes. Like glycine, ACPC enhanced 'H-labelled (+)-5-methyl-10,l I -dihydro-5H-dibenzo[a,d]cyclohepten-5, I O-imine maleate (['HIMK-80 1) binding to N-methyl-Baspartate receptorcoupled cation channels (ECSo, 135 & 76 &and 206 t 78 nM for ACPC and glycine, respectively) but was -40% less efficacious in this regard. The maximum increase in ['H]MK-80 1 binding produced by a combination of ACPC and glycine was not different from that elicited by glycine, but both compounds potentiated glutamate-stimulated ['H]MK-801 binding. These findings indicate that ACPC is a potent and selective ligand at the glycine modulatory site associated with the N-methyl-D-aspartate receptor complex. Key Words: 1-Aminocyclopropane carboxylic acid-Excitatory amino acid receptors-Glutamate-Glycine-MK-80 I -N-Methyl -D-aspartate. Marvizbn J.-C. G . et al. I-Aminocyclopropane carboxylic acid: A potent and selective ligand for the glycine modulatory site of the Nmethyl-D-aspartate receptor complex. J. Neurochem. 52, 992-994 ( I 989).
European Journal of Pharmacology: Molecular Pharmacology, 1991
A stwchnine-insensitive glycine binding site is located on the N-methyl-D-aspartate fNMDM-preferring ~utamate r~epter complex. Kynurenic acid analogs are antagonists at tl~s binding si!e. A derRative of kynurenic acid. ~.7-dicNorokynurenic acid (5,7-DCKA) was radiolabeled with ~H and used lo study antagonist binding to the glsviae r~zog~'~Jtior~ sue. TNs ~igand ([~HI5,7-DCKA) sho~ed high affinity (K e = 69 nM), saturable (B~, = t4.5 pmol/mg protein~ binding ~o rat brain membrane~. A variety of agonists and antagonists inhabited the binding of [SH]5,7-DCKA and [-~Hlglycine in a similar fa, hion ~r ~ 0,~3}. i~ addition, glutamate site agonists and antagonists exerted opposite at[os~enc effects on [~H]5.7-DCKA binding suggesting that [JH]5.7-DCKA pref:rentially binds to the agonist-activated conforma~ior~ of the receptor.
The Journal of Neuroscience, 1989
3-Amino-1-hydroxypyrrolid-2-one (HA-966) has been known for several years as an excitatory amino acid antagonist, acting principally at the N-methyl-D-aspartate (NMDA) receptor subtype. We report here that HA- 966 blocks NMDA responses through a selective interaction with the glycine modulatory site present within the receptor complex. In radioligand binding experiments, HA-966 inhibited strychnine- insensitive 3H-glycine binding to rat cerebral cortex synaptic plasma membranes with an IC50 of 17.5 microM. At concentrations up to 1 mM, HA- 966 caused minimal inhibition of radioligand binding to the transmitter recognition sites of the NMDA, quisqualate, or kainate receptor subtypes and was similarly inactive against the binding of 3H- strychnine to rat spinal cord/brain stem membranes. In electrophysiological experiments, HA-966 produced a selective block of NMDA responses in a rat cortical slice preparation. The degree of antagonism caused by HA-966 was maximal at 250 microM and wa...
Molecular Pharmacology, 1989
The interaction of newly described antagonist of the non-NMDA glutamate receptor 6-cyano-7-nitroquinoxaline-2,3-dione(CNQX) with the glycine site of the NMDA receptor complex has been investigated. In whole-cell patch recordings from hippocampal neurons maintained in culture, currents induced by N-methyl-Daspartate (NMDA) were dependent on extracellular glycine. Responses to both NMDA (30 pM) and kainate(20 pM) were reduced by CNQX (1 0-30 pM). The antagonism by CNQX of NMDA, but not kainate, receptor-mediated responses could be reversed by increasing the concentration of glycine in the external medium. Glycine concentration-response curves constructed in the presence of 30 ıcM NMDA were shifted to the right by CNQX, suggesting that CNQX was competing with glycine for the glycine binding site. However, even at high concentrations of glycine (300 pM) the maximal NMDA current obtained in the presence of CNQX (1 0-30 pM) was not restored to control levels. Because CNQX had no effect on responses produced by supramaximal concentrations of NMDA (500 pM) and glycine (300 pM), it is suggested that CNQX also interacts with the NMDA recognition site. The antagonism of currents induced by NMDA was not dependent on the membrane potential, and the rapid onset and offset of the block suggested that there was little or no use dependence. Radioligand binding experiments were performed using [3H]glycine to label the strychnine-insensitive glycine regulatory site of the NMDA receptor complex in guinea pig brain frontal cortex membranes. CNQX displaced [3H]glycine binding in a concentration-dependent manner (IC50 = 5.7 pM). Scatchard analysis of the inhibition showed a decrease in the affinity (increase in K0) of [3H]glycine binding, but no change in the number of binding sites (Bmax) in the presence of 5 pM CNQX, suggesting a competitive interaction. These data provide evidence that CNQX antagonizes NMDA receptor-mediated responses by competing with glycine for a modulatory site associated with the NMDA receptor complex. Furthermore, the results indicate that CNQX may not be as selective an antagonist for non-NMDA receptors as initially described, although its selectivity will depend on the concentration of the NMDA receptor ligand and may be enhanced by increasing the extracellular concentration of glycine.
An endogenous modulator of N-methyl-D-aspartate receptor-coupled glycine receptors
European Journal of Pharmacology: Molecular Pharmacology, 1990
Extensive washing of a membrane preparation from rat brain resulted in a pro~essive enhaacement of strychnineinsensitive [3H]glycine binding, which was due to an increase in the number of binding sites with no changes in the apparent affinity of this radioligand, precluding an explanation based solely on the elimination of endogenous glycine. Moreover, after extensive washing a population of [3H]glycine binding sites with very high affinity for L-serine was observed in addition to the sites with low affinity for L-serine present in less extensively washed tissue. The observed changes in [3H]glycine binding were attributable to the eli~_~ination of a low molecular weight, heat-stable compound which was readily detected in the wash supernatant. Extensive washing also altered [3H](-')-5-methyl-10A 1-dihydro-5H-dibenzo-[a,d]cyclohept-5,10-imine maleate ([3H]MK-801) binding to N-methyl-D-aspartate (NMDA) receptor-associated channels, decreasing basal binding at equilibrium and producing slower association rates in the presence of either glycine or L-ghitamate. Moreover, in well-washed membranes both glycine anti glutamate enhanced [3 H]MK-801 binding acting at high-and low-affinity sites. These findings suggest that the NMDA receptor complex can assume interconverting conformational states regulated by an endogenous substance(s).
2010
Harty, T. Patrick and Paul B. Manis. Kinetic analysis of glycine expression of whole brain DNA. Strychnine and picrotoxin receptor currents in ventral cochlear nucleus. J. Neurophysiol. 79: block the chloride-dependent conductance produced by gly-1891-1901, 1998. Glycine plays an important role as an inhibitory cine. Expressed homomerically, the b subunit is inactive, neurotransmitter in the ventral cochlear nucleus. However, little is whereas heteromeric expression of both a and b subunits known about the kinetic behavior of glycine receptors. The present results in receptors that are relatively insensitive to the chlostudy examines the kinetics of the native inhibitory glycine recepride channel blocker, picrotoxin (Pribilla et al. 1992). tors in neurons of the ventral cochlear nucleus, using outside-out Although the pharmacological and structural properties of patches from acutely dissociated cells and a fast flow system. Steps glycine receptors have been well characterized, the kinetics into 1 mM glycine revealed fast phases of desensitization with that govern receptor gating have not been investigated in time constants of 13 and 129 ms, that together produced a 40% reduction in current from the peak response. Slower desensitization detail. For example, very little has been reported on activaphases also were observed. After removal of glycine, currents deaction and deactivation kinetics. In the continued presence of tivated with two time constants of 15 and 68 ms, and these rates glycine, desensitization of whole cell currents occurs with were independent of the glycine concentration between 0.2 and 1 time constants that range from 0.5 s in hypothalamic neurons mM. Recovery from desensitization was slow relative to desensiti-(Akaike and Kaneda 1989) to 350 s in oocytes expressing zation itself. These results demonstrate that glycine receptors can the a subunit (Schmieden et al. 1989). However, the methexhibit faster rates of desensitization and deactivation than preods used in these studies were not optimal for measurement viously reported.
Journal of …, 1989
A [3H]glycine recognition site in rat brain synaptic plasma membranes (SPM) has been identified. having characteristics expected of a modulatory component of the A'methyl-waspartate receptor complex. Incubation of SPM with [3H]glycine for 10 min at 2°C results in saturable, reversible binding with a KD of 0.234 pA4 and a B,,, of 9.18 pmol/mg. A pharmacological analysis of this binding site indicates that Dserine (K, = 0.27 wM), D-alanine (K, = 1.02 p M) , and D-CyClOserine (K, = 2.33 p M) are potent inhibitors of binding, whereas the corresponding L isomers have significantly less activity (K, = 25.4 p M , 15.9 p M , and >I00 pM, respectively). Inactive at concentrations of up to 100 pM were strychnine, L-valine, N,N-dimethylglycine, ami
The Journal of pharmacology and experimental therapeutics, 1997
A series of novel tricyclic pyrido-phthalazine-dione derivatives was tested for antagonistic effects at the strychnine-insensitive modulatory site of the N-methyl-D-aspartate (NMDA) receptor (glycineB). All compounds displaced [3H]MDL-105,519 binding to rat cortical membranes with IC50 values of between 90 nM and 3.6 microM. In patch-clamp experiments, steady-state inward current responses of cultured hippocampal neurons to NMDA (200 microM, glycine 1 microM) were antagonized by these same compounds with IC50 values of 0.14 to 13.8 microM. The antagonism observed was typical for glycineB antagonists, i.e., they induced desensitization and their effects were not use or voltage dependent. Moreover, increasing concentrations of glycine were able to decrease their apparent potency. Much higher concentrations (>100 microM) were required to antagonize alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-induced currents. They were potent, systemically active NMDA receptor antagonis...