Glutamic Acid Binding Research Articles

Localization of [ 3H]glutamate binding sites in rat adrenal medulla

A significant activity of l-[ 3H]glutamic acid binding was detected in the membranous particulate preparations obtained from the rat adrenal glands. In vitro addition of sodium acetate (100 mM) resulted in a drastic enhancement of the binding to cerebral preparations, while inducing a significant inhibition of the adrenal binding. Quisqualic acid elicited a prominent suppression of the adrenal binding in a concentration-dependent manner to a slightly greater extent than the inhibition of cerebral binding. N-Methyl- d-aspartic acid exerted a significant stimulatory action on the adrenal binding without affecting the cerebral binding. The adrenal medullary part possessed more than 5-fold higher binding activity than that in cortical part. These results suggest the possible existence of [ 3H]glutamate binding sites in rat adrenal glands which are distinctly different from those in the central structures.

Development of a micromethod to study the Na +-independent l-[ 3H]glutamic acid binding to rat striatal membranes. I. Biochemical and pharmacological characterization

A micromethod was developed to measure the Na +-independent l-[ 3H]glutamic acid (Glu) binding to rat striatal membranes by using slightly purified membranes from very small tissue amounts, ranging from 0.2 to 0.5 mg wet tissue. The specific binding reached equilibrium in about 30 min incubation at 37 °C and was shown to be partly reversible. Scatchard's analysis of saturation data suggests the presence on striatal membranes of an apparent single homogeneous population of Na +-independent binding sites with K d value 1.75 μM and B max 3.89 nmol/g protein. Hill's plot of these data was linear, with slope not significantly different from unity, indicating the absence of cooperative interactions. Cl − and Ca 2+ ions were shown to severely influence the l-[ 3H]Glu binding to striatal tissue. Maximal activating effects were obtained in the presence of both ions, although Cl − alone was shown to have a powerful stimulating action on the binding. Pharmacological studies suggested, however, the presence of at least two subpopulations of binding sites which bound quisqualic acid as well as ibotenic acid with differential affinities. l-aspartic acid and l-serine-O-sulfate were shown to be potent inhibitors of the l-[ 3H]Glu binding when dl-2-amino-4-phosphonobutyric acid ( dl-APB) and glutamic acid diethylester (GDEE) competed with the binding but only at high concentrations. N-methyl- d-aspartic acid (NMDA), dl-2-amino-5-phosphonovaleric acid ( dl-APV), d-α-aminoadipate ( d-αAA) and kainic acid were shown not to significantly influence the binding of Glu to striatal membranes

Development of a micromethod to study the Na +-independent l-[ 3H]glutamic acid binding to rat striatal membranes. II. Effects of selective striatal lesions and deafferentations

An apparent single class of Na +-independent l-[ 3H]glutamate ( l-[ 3H]Glu) binding sites was biochemically and pharmacologically identified on rat striatal tissue. The K d value was 1.75 μM and the B max3.89 nmol/g protein. In order to further elucidate the putative physiological role of these binding sites and to valid our binding assay, experiments were conducted to determine the anatomical location of the l-[ 3H]Glu binding sites in the striatum. Local injection of the neurotoxin, kainic acid into the striatum caused degeneration of target cells in the structure followed by an important decrease (-37%) in the number of these binding sites, with no significant change in the affinity constant. Lesions of the cortical frontal and parietal areas projecting to the striatum via putative glutamatergic fibers led, on the other hand, after 3 weeks to one month, to a significant increase (+23%) in the number of l-[ 3H]Glu binding sites. The K d value does not significantly change after decortication. Finally, suppression either of the nigrostriatal dopaminergic input or of the partially cholinergic thalamostriatal tract do not affect [ 3H]Glu binding to striatal tissue. These results suggest that about 40% of our [ 3H]Glu binding sites are located on striatal target cell sensitive to the neurotoxic effect of kainic acid. Therefore, they seem to be partly postsynaptic. The existence of a relation between these binding sites and the corticostriatal glutamatergic input was shown by the development of a supersensitivity response after suppression of this cortical input. These sites might therefore constitute one of the receptor subclass for Glu linked to the excitatory action of the corticostriatal afferent. Since degeneration of either the nigrostriatal dopaminergic or the thalamostriatal fibres did not affect the binding of l-[ 3H]Glu characterized in our study, the binding sites will probably not occur at the presynaptic level on these nerve terminals in the striatum.

Stability of sialogangliosides in kindled hippocampus

Altering ganglioside concentration can modulate l-[ 3H]glutamic acid binding to synaptic membranes in vitro. This study indicates that a recently reported increase of hippocampal l-glutamate receptor density observed with entorhinal kindling is not associated with a quantitative change in hippocampal neuronal membrane sialoganglioside.

Lack of effect of entorhinal kindling on l-[ 3H]glutamic acid presynaptic uptake and postsynaptic binding in hippocampus

Sodium-independent l-[ 3H]glutamic acid binding and sodium-dependent l-[ 3H]glutamic acid high affinity uptake were measured in hippocampal membranes of rats administered electroshock seizures or kindled to class 5 seizures by entorhinal cortical stimulation. There were no differences in these glutamatergic synaptic markers among electroshocked, kindled, or surgical control animals. Entorhinal kindling is not a reflection of activity-regulated facilitation of perforant path glutamatergic neurotransmission.

Sodium-independent glutamic acid binding in cultured fibroblasts from patients with Huntington's disease

Glutamic acid, in the absence of sodium, binds to a single population of binding sites in the fibroblast membrane with a dissociation constant (K(d)) in the nanomolar range, similar to those obtained in human and rat cortices. The density of binding sites (B(max)) in fibroblast membranes from patients with Huntington's disease was only 54% of that in control membranes.

Glutamic acid binding in goldfish brain and denervated optic tectum

The binding of L-glutamic acid to goldfish brain membranes and changes in tectal binding following optic nerve denervation and regeneration were investigated. Saturable, reversible, and specific binding occurred to sodium-free washed membranes from goldfish brain at a single population of sites having an apparent Kd of 3.4 microM and a capacity of 10 pM/mg original tissue. Binding was enriched in crude synaptosomal (P2) subcellular fractions. There was a 10-fold regional variation in the concentration of binding sites. In pharmacological studies protection constants (Kp) (the concentration which resulted in a 50% inhibition of binding) ranged from 4 microM for glutamate to greater than 10 mM for GABA. Following eye removal, the total number of tectal glutamic acid binding sites was stable for 4 days, followed by a rapid loss in binding, reaching 40% of control at 24 days. After optic nerve crush and optic nerve regeneration, the number and concentration of binding sites was not different from control. The relationship between glutamate, nicotinic, and muscarinic receptor sites in the retinotectal pathway is discussed.

Ibotenic acid analogues as inhibitors of [3H]glutamic acid binding to cerebellar membranes.

The L-[3H]glutamic acid binding capability of rat cerebellar membranes prepared with or without preincubation at 37 degrees C followed by washing was investigated. The two preparations (KD = 820 nM, Bmax = 54.5 pmol/mg protein; KD = 509 nM, Bmax = 13.0 pmol/mg protein) showed no difference in specificity of the binding of the ibotenic acid analogues, consistent with the removal of an endogenous inhibitor by the preincubation at 37 degrees C followed by washing. The order of potency of the ibotenic acid analogues as inhibitors of L-[3H]glutamic acid binding is different from the order of potency in vivo, suggesting that the binding sites found are different from the physiological glutamic acid receptor.

Distinguishing characteristics between glutamate and kainic acid binding sites in brain synaptic membranes

The demonstration of strong neuroexcitatory activity produced by extracellular application of L-glutamic and L-aspartic acid [l-4] has led to biochemical studies aimed at defining the membrane sites with which these putative neurotransmitters interact [S-lo]. The pursuit of the biochemical characterization of the excitatory amino acid receptor sites has been conducted along two lines: (1) Determination of membrane binding activity through the use of radioactively labeled glutamate or aspartate [5-81; or (2) Measurement of the receptor recognition function through the use of radioactively labeled kainic acid (2-carboxy-4-isopropenyl-3-pyrrolidine acetic acid) [9,10], a potent neuroexcitatory agent which is presumed to act on the excitatory amino acid receptors [ 11,121. We have shown that brain synaptic membranes are enriched in high affinity L-[3H]glutamic acid binding sites which have a number of the pharmacologic characteristics of the receptor for this excitatory amino acid [5,13,14]. It was also shown that this high affmity glutamate binding activity of synaptic membranes is associated with a small molecular weight glycoprotein [ 151. Glutamate binding to this protein exhibits a similar pattern of sensitivity to various glutamate analogs as does the binding of L-glutamate to the synaptic membranes [5,14,15]. However, the binding of L-[3H]glutamic acid either to the synaptic membranes [6,14] or to the purified binding protein [14] is not affected by the presence of a 103-fold greater concentration of kainic acid. Evidence is provided here which is strongly suggestive of the distinct nature of the membrane macromolecules which function as the binding sites for L-glutamic acid and those for kainic acid.

EFFECT OF ALKALI-EARTH CATIONS ON FROG SPINAL GANGLION CELL.

ArticlesEFFECT OF ALKALI-EARTH CATIONS ON FROG SPINAL GANGLION CELLS. Nishi, H. Soeda, and K. KoketsuS. Nishi, H. Soeda, and K. KoketsuPublished Online:01 May 1965https://doi.org/10.1152/jn.1965.28.3.457MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByEffects of inorganic potassium channel blockers on calcium requirement of transmission in a sympathetic ganglionJournal of the Autonomic Nervous System, Vol. 34, No. 2-3A method for evoking physiological responses by stimulation of cell bodies, but not axons of passage, within localized regions of the central nervous systemJournal of Neuroscience Methods, Vol. 6, No. 4S-glutamate: Its interactions with spinal neuronsBrain Research Reviews, Vol. 3, No. 3Electrophysiology, acetylcholine and acetylcholinesterase of immature spinal ganglia of the rabbit—An experimental study and a reviewGeneral Pharmacology: The Vascular System, Vol. 11, No. 1Effects of barium on some stimulus evoked inhibitory post-synaptic potentials in the brain of Helix pomatiaComparative Biochemistry and Physiology Part A: Physiology, Vol. 58, No. 2Analysis of amino acid responses on frog motoneuronesNeuropharmacology, Vol. 15, No. 1High-affinity glutamic acid binding to brain synaptic membranesBiochimica et Biophysica Acta (BBA) - Biomembranes, Vol. 367, No. 3Divalent cations as charge carriers in excitable membranesProgress in Biophysics and Molecular Biology, Vol. 26Effects of alkali-earth cations on sympathetic ganglion cells of the rabbitLife Sciences, Vol. 11, No. 20Excitation of mammalian central neurones by acidic amino acidsBrain Research, Vol. 41, No. 2The antagonism of the glutamate-induced and synaptic excitations of thalamic neuronesBrain Research, Vol. 39, No. 2Evidence for cerebral membrane effects of calcium, derived from direct-current gradient, impedance, and intracellular recordsExperimental Neurology, Vol. 30, No. 1The role of calcium ions in the action potentials of Helix aspersa neuronesComparative Biochemistry and Physiology, Vol. 20, No. 1Effects of tetrodotoxin on the action potential in NA-free mediaLife Sciences, Vol. 5, No. 24 More from this issue > Volume 28Issue 3May 1965Pages 457-472 https://doi.org/10.1152/jn.1965.28.3.457PubMed14328446History Published online 1 May 1965 Published in print 1 May 1965 Metrics