Beneficial effects of xenon inhalation on behavioral changes in a valproic acid-induced model of autism in rats.

BACKGROUND: Xenon (Xe) is a noble gas that has been used for the last several decades as an anesthetic during surgery. Its antagonistic effect on glutamate subtype of NMDA (N-methyl-D-aspartate) receptors resulted in evaluation of this gas for treatment of CNS pathologies, including psychoemotional disorders. The aim of this study was to assess the behavioral effects of acute inhalation of subanesthetic concentrations of Xe and to study the outcomes of Xe exposure in valproic acid (VPA)-induced rodent model of autism. METHODS: We have conducted two series of experiments with a battery of behavioral tests aimed to evaluate locomotion, anxiety- and depression-like behavior, and social behavior in healthy, VPA-treated and Xe-exposed young rats. RESULTS: We have shown that in healthy animals Xe exposure resulted in acute and delayed decrease of exploratory motivation, partial decrease in risk-taking and depressive-like behavior as well as improved sensorimotor integration during the negative geotaxis test. Acute inhalations of Xe in VPA-exposed animals led to improvement in social behavior, decrease in exploratory motivation, and normalization of behavior in forced-swim test. CONCLUSION: Behavioral modulatory effects of Xe are probably related to its generalized action on excitatory/inhibitory balance within the CNS. Our data suggest that subanesthetic short-term exposures to Xe have beneficial effect on several behavioral modalities and deserves further investigation.

[Food-derived opioid peptides and their neurological impact].

In this review the up-to-date literature data about exorphins are analysed. Exorphins are short opioid-like food-derived peptides. Different reports about their physiological impact in animals and humans are reviewed with focus on neurotropic effects. Clinical data (case reports and clinical trials' results), on the one hand, and the results of experiments with animals of different taxons, on the other hand, are summarized. The influence of exorphins on infants' development is emphasized.

[Effects of several exorphins and endorphins on the escape reaction of the cockroach Periplaneta americana under elevated temperature conditions].

The ability of several alimentary opioid peptides (exorphin C, rubiscolin-5, cytochrophi-4) and endorphins (met-enkephalin, dynotphin A(1-10), beta-neoendorphin) to change the escape reaction of the cockroaches Periplaneta americana at their placement into a hot chamber was studied. The ED50 values increasing twice the insect stay time in the hot chamber as well as duration and dynamics of the effects were determined. It has been shown that ED5 decreases statistically significantly with increase of the length of the peptide molecule and its affinity of duration of the effects and to an increase of their affinity to delta-receptors - to prolongation of the reaction (more than150 min). In the group of alimentary peptides (exorphins) the most active was a fragment of D-ribulose-1,5-biphosphate carboxylase/oxigenase rubiscolin-5 (ED5 = 386 nM per individual). This might indicate a specific ability of some plant proteins to regulate (decrease) the insect protective behavior.

Spontaneous activity of individual neurons in the human ventrolateral thalamus during changes in the functional state of the brain.

Background spike activity of 235 cells of the integrative subcortical motor center, i.e., the ventrolateral nucleus of the thalamus, were analyzed in nonanesthetized human brains during stereotaxic surgery in patients with various forms of Parkinson's disease. Previous data on the existence of two major types of neurons with convergent properties in the ventrolateral nucleus were confirmed. These cell types are: 1) cells with irregular occasional activity, with a tendency for spikes to group into the frequency ranges 5 +/- 1 and 10-30 Hz (type A cells, 74%), and 2) cells with constant rhythmic (3-6 Hz) generation of short volleys of discharges, with an interval structure similar to that of low-threshold Ca(2+)-dependent volley activity (type B, 26%). This is the first report demonstrating that changes in the functional state of the brain (after repeated movement trials, in transient anesthesia) are accompanied by transiently occurring transformations of the initial irregular activity of A cells into a rhythmic, volley-like pattern whose interval structure was in some cases similar to the spike activity of B cells. Differences in the localizations of A and B neurons in the ventrolateral nucleus are described, along with differences in the correlation characteristics of their background spike activity with the pathological features of Parkinson's disease (tremor, rigidity). The nature of the two types of convergent neurons in the ventrolateral nucleus is discussed, and a basis is laid for the importance of the functional factor in understanding the transformation of their background spike activity, due to the properties of cell membranes and intercellular and interstructure interactions in conditions of the living nonanesthetized human brain.