Expression of NMDA neuroreceptors in experimental ischemia.

The role of NMDA receptors in molecular mechanisms of neurotoxicity was investigated using rat models of global and focal cerebral ischemia. Expression of NR2A and NR2B receptor mRNAs up-regulated in cortex after 3 h of reperfusion following middle cerebral artery occlusion (MCAo). This effect was accompanied by an increase in NR2A and NR2B immunoreactivity. At six hours of reperfusion, drastic activation of NR2A mRNA expression was observed in the penumbra that returned to the control level at 24 h of reperfusion. The monitoring of NR2A autoantibodies in the blood of the experimental rats showed its reliable increase to the 5-6th day of reperfusion that maintained elevated to the 20th day of the experiment. The data indicate that NR2A and 2B receptor subunits and NR2A autoantibodies are biochemical markers of the neurotoxicity underlying cerebral ischemia.

[The use of the clinical biochemical Epitest kit in children with epilepsy]. / Primenenie kliniko-biokhimicheskogo nabora "Epitest" u detei s épilepsiei.

57 children aged 3-15 years were examined: children with epilepsy (n = 26), children with epileptic syndrome (n = 16) and children with other neurologic pathology (n = 15). Control group included 25 healthy children. Diagnostic efficiency of the epileptic test was investigated on the basis of the detection of autoantibodies (aAb) to glutamate receptor of AMPA type in blood serum of the patients. It was shown that children with epilepsy had elevated level of aAb to AMPA receptors in blood in comparison with that of the healthy children. The level of aAb to AMPA receptors correlated with severity of the disease and location of the epileptic focus. The authors recommend the "Epitest" as an additional biochemical tool for differential diagnosis of children's epilepsy.

Monitoring of brain spiking activity and autoantibodies to N-terminus domain of GluR1 subunit of AMPA receptors in blood serum of rats with cobalt-induced epilepsy.

We have monitored EEG spontaneous spiking activity and analyzed serum from rats with cobalt-induced epilepsy for the presence of autoreactive antibodies to alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) glutamate receptor subunits. The presence and the level of autoantibodies were assessed using immunoblot and ELISA with synthetic peptide specific to the N-terminus domain of the GluR1 subunit of the AMPA receptor. Rats with cobalt-induced epilepsy exhibited strong GluR1 immunoreactivity at the end of the first week after surgery compared with vehicle-treated rats. We showed that GluR1 autoantibodies in blood serum of rats with cobalt-induced epilepsy preceded the spiking activity maximum in the EEG. Levels of autoantibodies to GluR1 detected in blood of these rats remained elevated when EEG spiking activity was significantly reduced and seizures disappeared. The EEG monitoring of spiking activity showed a correlation with accumulation of GluR1 autoantibodies in blood serum of rats with cobalt-induced epilepsy.

The presence of autoantibodies to N-terminus domain of GluR1 subunit of AMPA receptor in the blood serum of patients with epilepsy.

We have analyzed the serum from patients with refractory epilepsy for the presence of autoreactive antibodies to AMPA glutamate receptor subunits. The presence and the level of autoantibodies were assessed using immunoblot and ELISA with synthetic peptides specific for subregions of AMPA glutamate receptor subunits. Patients with refractory epilepsy exhibited strong immunoreactivity to GluR1 subunit compared to healthy donors and patients with Parkinson's disease and Alzheimer's disease. Weak immunoreactivity to other AMPA glutamate receptor subunits was also detected and the signal was diminished in the raw GluR4>GluR3>GluR2. The occurrence of autoantibodies to specific neurotransmitter subunits in the sera of patients with refractory epilepsy suggest that autoimmune process may underlie this disorder.

[Autoantibodies to glutamate receptor subtypes--markers of functional brain damage: their diagnostic significance for detecting paroxysmal activity and ischemia]. / Autoantitela k podtipam glutamatnykh retseptorov--markery funktsional'nogo porazheniia golovnogo mozga: ikh diagnosticheskoe znachenie dlia vyiavleniia paroksizmal'noi aktivnosti i ishemii.

A new direction in diagnostics and the control of pharmacological treatment of brain disorders is discussed. Problems which are considered in the review have significance for understanding the neurochemical mechanisms of paroxysmal activity and brain ischemic stroke. The identification of autoantibodies for glutamate receptors, thought to be involved in these brain disorders, presents a new approach toward characterization of clinical states of individuals and could have a wide application for control of efficiency of pharmacological treatments.

[The level of autoantibodies to glutamate receptors in the blood serum of patients in the acute period of ischemic stroke]. / Izuchenie urovnia autoantitel k glutamatnym retseptoram v syvorotke krovi u bol'nykh v ostrom periode ishemicheskogo insul'ta.

The level of autoantibodies (aAB) to main structural component of glutamate NMDA-receptors--phencyclidin-binding protein--was measured in blood serum of 70 patients during first 3, 6, 9, 12, 24 hours, and 3, 5 days after ischemic stroke development. 200 healthy individuals formed the control group. The elevation of titers of aAB to glutamate receptors was observed in all patients with severe or moderate disease from the very first hours of stroke. It was especially pronounced by 9-12 hours after stroke. The highest increase of aAB titers was found in severe cases. The tendency to normalization of aAB titers was observed by the end of the first twenty four hours. The degree of aAB elevation had the prognostic importance. The most favourable course of stroke with good restoration of damaged functions was predicted when stable normalization of the aAB level was observed by the third day of the disease development. Patients in stupor-coma condition did not show the phenomenon of aAB level's elevation during the first days of stroke, that reflected, probably, the development of immuno-deficient state. The decrease of aAB level down to subnormal values was extremely unfavourable prognostic sign proceeding patient's death as a rule.

[Dalargin-binding proteins of synaptic membranes from the rat brain: isolation and comparison of their properties with opiate receptor properties]. / Dalarginsviazyvaiushchie belki sinapticheskikh membran mozga krys: vydelenie i sravnenie ikh svoistv so svoistvami opiatnykh retseptorov.

The proteins isolated from rat brain synaptic membranes were studied by affinity chromatography on dalargin-omega-aminohexyl-Sepharose 4B and specific elution with DAGO (Tyr-D-Ala-Gly-N-Me-Gly-ol). These proteins were shown to bind specifically 3H-naloxone (Kd = 6.6 nM; Bmax = 690 pmol/mg of protein). SDS electrophoresis of the dalargin-binding proteins termed as DBPDAGO revealed one major protein band with M(r) of 42 kDa and two minor bands with M(r) of 29 and 67 kDa. The glycoprotein component was found in DBPDAGO; their isoelectric properties were established (pI 5.4). The close similarity of DBP properties with those of isolated brain opiate receptors suggest them to be opiate receptor components.

[Effects of paradoxical sleep deprivation on the activity of opiate receptors isolated from synaptic membranes of the rat brain]. / Vliianie lisheniia paradoksal'noi fazy sna na aktivnost' opiatnykh retseptorov, izolirovannykh iz sinapticheskikh membran mozga krys.

The specific binding of 3H-naloxone with opiate receptors isolated from brain synaptic membranes of control and paradoxical sleep deprived rats were studied. This extreme state was shown to reduce the naloxone-binding activity of synaptic membranes by 35% and isolated receptors by 25-28%. The values of Kd and Bmax were calculated for isolated opiate receptors at different stages of purification. Considerable decrease of 3H-naloxone binding sites density (2 times) in the isolated opiate receptors with simultaneous increase of their affinity (3-4,5 times) was found following 24 hours paradoxical sleep deprivation. These findings suggest development of fixed alterations in the structure and functions of integral receptor proteins under extreme influences.