skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Glutamate and glycine modulation of 3H-MK801 binding to the NMDA receptor-ion channel complex in the vitamin B-6 deficient neonatal rat brain

Abstract

The authors have previously shown that the concentrations of the neuroactive amino acids glutamate (GLU) and glycine (GLY) are significantly altered in the seizure-prone vitamin B-6 deficient neonatal rat brain. Recently, it has been shown that GLU and GLY modulate the binding of {sup 3}H-MK801 to the ion channel associated with the N-methyl-D-aspartate (NMDA)-glutamate receptor subtype. The present investigation was undertaken to determine if GLU or GLY modulation of {sup 3}H-MK801 binding was altered in B-6 deficient neonatal rat brain. Preparation of cortical membranes from control and deficient 14 day old rats and {sup 3}H-MK801 binding assay were done as described by Ransom and Stec. The results show a significant reduction in the potency and efficacy of GLU modulation of {sup 3}H-MK801 binding, as well as a reduction in the efficacy of GLY, in membrane preparations from deficient rats compared to controls. These results indicate a reduced ability of GLU and GLY to potentiate the binding of {sup 3}H-MK801 to the NMDA receptor-ion channel in the B-6 deficient neonatal rat brain.

Authors:
 [1]
  1. (Johns Hopkins Univ., Baltimore, MD (United States))
Publication Date:
OSTI Identifier:
6057291
Alternate Identifier(s):
OSTI ID: 6057291
Report Number(s):
CONF-9104107--
Journal ID: ISSN 0892-6638; CODEN: FAJOE
Resource Type:
Conference
Resource Relation:
Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States); Journal Volume: 4:3; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; GLUTAMIC ACID; BIOLOGICAL EFFECTS; GLYCINE; PYRIDOXINE; BIOCHEMICAL REACTION KINETICS; BRAIN; NEONATES; NUTRITIONAL DEFICIENCY; RATS; RECEPTORS; TRACER TECHNIQUES; TRITIUM COMPOUNDS; AMINO ACIDS; ANIMALS; AZINES; BODY; CARBOXYLIC ACIDS; CENTRAL NERVOUS SYSTEM; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; HYDROXY COMPOUNDS; ISOTOPE APPLICATIONS; KINETICS; MAMMALS; MEMBRANE PROTEINS; NERVOUS SYSTEM; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANS; PROTEINS; PYRIDINES; REACTION KINETICS; RODENTS; VERTEBRATES; VITAMIN B GROUP; VITAMINS 550201* -- Biochemistry-- Tracer Techniques

Citation Formats

Guilarte, T.R. Glutamate and glycine modulation of 3H-MK801 binding to the NMDA receptor-ion channel complex in the vitamin B-6 deficient neonatal rat brain. United States: N. p., 1990. Web.
Guilarte, T.R. Glutamate and glycine modulation of 3H-MK801 binding to the NMDA receptor-ion channel complex in the vitamin B-6 deficient neonatal rat brain. United States.
Guilarte, T.R. Mon . "Glutamate and glycine modulation of 3H-MK801 binding to the NMDA receptor-ion channel complex in the vitamin B-6 deficient neonatal rat brain". United States. doi:.
@article{osti_6057291,
title = {Glutamate and glycine modulation of 3H-MK801 binding to the NMDA receptor-ion channel complex in the vitamin B-6 deficient neonatal rat brain},
author = {Guilarte, T.R.},
abstractNote = {The authors have previously shown that the concentrations of the neuroactive amino acids glutamate (GLU) and glycine (GLY) are significantly altered in the seizure-prone vitamin B-6 deficient neonatal rat brain. Recently, it has been shown that GLU and GLY modulate the binding of {sup 3}H-MK801 to the ion channel associated with the N-methyl-D-aspartate (NMDA)-glutamate receptor subtype. The present investigation was undertaken to determine if GLU or GLY modulation of {sup 3}H-MK801 binding was altered in B-6 deficient neonatal rat brain. Preparation of cortical membranes from control and deficient 14 day old rats and {sup 3}H-MK801 binding assay were done as described by Ransom and Stec. The results show a significant reduction in the potency and efficacy of GLU modulation of {sup 3}H-MK801 binding, as well as a reduction in the efficacy of GLY, in membrane preparations from deficient rats compared to controls. These results indicate a reduced ability of GLU and GLY to potentiate the binding of {sup 3}H-MK801 to the NMDA receptor-ion channel in the B-6 deficient neonatal rat brain.},
doi = {},
journal = {FASEB Journal (Federation of American Societies for Experimental Biology); (United States)},
number = ,
volume = 4:3,
place = {United States},
year = {Mon Feb 26 00:00:00 EST 1990},
month = {Mon Feb 26 00:00:00 EST 1990}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • A dietary deficiency of vitamin B-6 promotes seizure activity in neonatal animals and human infants. Previous studied have shown that neonatal vitamin B-6 deprivation results in reduced levels of brain gamma-aminobutyric acid (GABA) and increased binding at the GABA site of the GABA/BDZ receptor complex. Since the GABA and BDZ receptors are allosterically linked, this study was undertaken to determine if vitamin B-6 deprivation had an effect on BDZ receptor binding. Benzodiazepine receptor binding isotherms using {sup 3}H-flunitrazepam as ligand were performed in the presence and absence of 10 {mu}M GABA. The results indicate a significant increase in the bindingmore » affinity (Kd) in the presence of GABA in cerebellar membranes from deficient rat pups at 14 days of age with no effect on receptor number (Bmax). By 28 days of age, the increase in Kd was no longer present. No change in Kd or Bmax was observed in cortical tissue from deficient animals at 14 or 28 days of age. Preliminary studies of GABA-enhancement of {sup 3}H-flunitrazepam binding indicate that vitamin B-6 deficiency also induces alterations in the ability of GABA to enhance BZD receptor binding. In summary, these results indicate that the effects of vitamin B-6 deprivation on BDZ receptor binding are region specific and age related.« less
  • The effect of temperature on the binding of ({sup 3}H)-N-(1-(2-thienyl)cyclohexyl)piperidine (({sup 3}H)TCP) to the ion channel of the N-methyl-D-aspartate (NMDA) receptors was studied in washed rat brain-cortex membranes. Raising the temperature from 5 to 33{degree}C resulted in a significant increase in the association rates of ({sup 3}H)TCP binding measured in the presence of 1 {mu}M glutamate and 1 {mu}M glycine, but was less effective in the absence of the added agonists. No such effects of temperature on the dissociation rates of ({sup 3}H)TCP-receptor complexes were observed. In the absence of agonists, neither the association nor the dissociation binding components variedmore » with temperature, suggesting a diffusion-controlled limitation of access of the ligand to its site within the nonactivated NMDA receptor. No evidence was found for a temperature-dependent change in the density of ({sup 3}H)TCP binding sites or for heterogeneity of ({sup 3}H)TCP binding sites associated with the NMDA receptor, even though when approaching equilibrium the binding kinetics in the presence of glutamate and glycine deviated from an ordinary bimolecular reaction scheme. The data were fitted instead to a two-exponent binding function, comprising the sum of a fast and a slow binding component. The results suggest homogeneity of ({sup 3}H)TCP-binding domains within the NMDA receptor channel but variability of total channel opening time. The observed effects of glutamate and of glycine on the kinetic components are consistent with this suggestion.« less
  • Biochemical and electrophysiological studies have demonstrated that phencyclidine (PCP) recognition site exists in the ion channel of the N-methyl-D-aspartate (NMDA) receptor ion channel complex. Using an extensively washed rat cortical membrane preparation, the effects of Mg2+ and guanylylimidodiphosphate (GppNHp) were examined on the binding of (3H)-N-(1-(2-thienyl)cyclohexyl)-3,4-piperidine ((3H)TCP). Low concentrations of Mg2+ (EC50 = 11 microM) stimulated (3H)TCP binding under the basal condition and high concentrations of Mg2+ (IC50 = 1 mM) inhibited it. In the presence of 10 microM L-glutamate and 10 microM glycine, their EC50 values for Mg2+ enhancement of (3H)TCP binding were markedly reduced (to 1.9 microM ormore » 8.4 microM), respectively. By contrast, the IC50 values for Mg2+ inhibition of (3H)TCP binding were reduced in the presence of L-glutamate, but not glycine. Furthermore, a stimulatory effect of Mg2+ on (3H)TCP binding was additional to the (3H)TCP binding stimulated by a maximally effective concentration of L-glutamate (10 microM) or glycine (10 microM). In the kinetic study, 300 microM Mg2+ produced an increase in the rates of both association and dissociation of (3H)TCP. Similar results were obtained with L-glutamate (10 microM) and glycine (10 microM); 10 mM Mg2+ also caused an acceleration of the association rate but strongly decreased (3H)TCP binding at equilibrium. Compared with (3H)TCP binding under the basal condition, K+ (10 mM) alone decreased the maximal binding without producing any change in the association rate; 10 mM K+ also significantly decreased Mg(2+)-stimulated (3H)TCP binding but caused no change in the acceleration of the association rate caused by Mg2+.« less
  • Recent studies indicate that intoxicating concentrations of EtOH inhibit neuronal responses to activation of NMDA-type glutamate receptors. The authors have observed that the potency of different alcohols for inhibiting NMDA-activated ion current in hippocampal neurons increases as a function of increasing hydrophobicity, suggesting that EtOH acts at a hydrophobic site. To further characterize the mechanisms of this effect, the authors examined the voltage-dependence of the EtOH inhibition of NMDA-activated ion current as well as potential interactions of EtOH with other effectors of the NMDA receptor/ionophore complex. The amount of inhibition of peak NMDA-activated current by 50 mM EtOH did notmore » differ over a range of membrane potentials from {minus}60 to +60 mV, and EtOH did not alter the reversal potential of NMDA-activated current. The percent inhibition observed in the presence of 10-100 mM EtOH did not differ with NMDA concentrations from 10-100 {mu}M. The percent inhibition by 50 mM EtOH (30-48%) did not differ in the absence or presence of the channel blockers Mg{sup 2+} (50-500 {mu}M), Zn{sup 2+} (5 and 20 {mu}M) or ketamine (2 and 10 {mu}M), or with increasing concentrations of the NMDA receptor cofactor glycine (0.01-1 {mu}M). These data indicate that: (i) EtOH does not change the ion selectivity of the ionophore, and (ii) EtOH does not appear to interact with previously described binding sites on the NMDA receptor/ionophore complex.« less
  • Holley et al have reported that uptake and retention of a tracer dose of (/sup 3/H)-estradiol (E/sub 2/) by rat uteri nuclei was increased four-fold in pyridoxine-deprived young rats as compared to controls. The diet lacked a specific input of zinc, a nutrient which may also influence estrogen impact on target cells. The authors have tested the effect of diets restricted in either zinc or pyridoxine singly or in combination upon both retention of estrogen and subcellular distribution of estrogen receptor in rat uterus. Female Sprague-Dawley rats were fed their respective diets for five weeks. Stage of estrous cycle wasmore » determined by examination of vaginal smears. On the morning of estrous, each rat was given an IP injection of (/sup 3/H) E/sub 2/. Nuclear and cytosolic E/sub 2/ was determined after 20 minutes. A second series of animals were killed at estrous after the same period of dietary treatment and nuclear and cytosolic estradiol receptors were measured. Uterine retention of injected E/sub 2/ was increased 2-fold when Zn was limiting (3 ppm), 1.5-fold when B/sub 6/ was low and 3.5-fold when both were low. Dually deficient rats displayed a 10-fold increase in nuclear content of E/sub 2/ receptor but no significant change in total cellular receptor content.« less