Glutamate receptoes

Cognitive deficit is a frequent non-motor symptom in Parkinson's disease (PD) with an unclear pathogenesis. Recent research indicates possible involvement of insulin resistance and glutamate excitotoxicity in PD development. We investigated cognitive performance and the brain glutamate and insulin signaling in a rat model of PD induced by bilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA). Cognitive functions were assessed with Passive Avoidance (PA) and Morris Water Maze (MWM) tests. The expression of tyrosine hydroxylase (TH) and proteins involved in insulin (insulin receptor - IR, phosphoinositide 3 kinase - pI3K, extracellular signal-regulated kinases-ERK) and glutamate receptor (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptos-AMPAR, N-methyl-D-aspartate receptor - NMDAR) signaling was assessed in the hippocampus (HPC), hypothalamus (HPT) and striatum (S) by immunofluorescence, Western blot and enzyme-linked immunosorbent assay (ELISA)...

The main criteria asked to a GABAergic synapse, have been fulfilled by GABA at the recepto-neural junction of the sensory periphery of vestibular organs in vertebrates. These criteria include the demonstration of its precursor, its synthesizing and degrading (inactivating) mechanisms and their localization with the right polarity of a GABAergic synapse. A novel GABA depolarizing action with particular pharmacological characteristics and expression of subunits of GABA receptors of the synaptic type (GABAA, GABAB or a putative mixed GABAA-GABAC) that could account for these properties are discussed...

Recombinant fragments of the kainate-selective glutamate recepto subunit GluR-6 were expressed in insect cells and analysed for [3H]kainate binding activity in order to characterize the structural determinants responsible for ligand recognition. Deletion of the N-terminal approximately 400 amino-acid-residue segment and the C-terminal approximately 90 residues resulted in a membrane-bound core fragment which displayed pharmacologically native-like [3H]kainate binding properties. Further replacement of the membrane-embedded segments M1-M3 by a hydrophilic linker peptide gave rise to a soluble polypeptide which was accumulated in the culture medium...

Ionotropic glutamate receptors are composed of homomeric or heteromeric configurations of glutamate receptor subunits. We have cloned a member of a novel class of the rat ionotropic glutamate receptor family, termed chi-1. This subunit exhibits an average identity of 27% to NMDA subunits and 23% to non-NMDA subunits. Regional transcript levels of chi-1 are elevated just prior to and during the first postnatal week, with the highest levels present in the spinal cord, brainstem, hypothalamus, thalamus, CA1 field of the hippocampus, and amygdala...

The preferable conformations of the inhibitory transmitter gamma-aminobutyric acid (GABA) and its specific inhibitor bicuculline are due to the occupation of the GABAreceptor by a part of the bicuculline molecule that is isosteric with the biologically active conformation of GABA. In the present review are described characteristics of sodium-independence receptor sites and evaluated the regional distribution of postsynaptic receptor binding for GABA in the central nervous system. The postsynaptic GABA receptor has been labeled by direct binding of 3H-GABA...