Morphometric and electrophysiologic research on the parafascicular complex of the thalamus in early ontogeny in the rabbit

Electrophysiological, morphometric and behavioural studies have been made on the role of parafascicular complex in regulation of nociceptive sensitivity in 45 rabbits from the 1st to the 16th day of their postnatal life. The evoked potential to nociceptive stimulation was recorded already in 1-day animals. Analysis of amplitude-temporal parameters of the EPs in acute experiments revealed a sharp increase in their positive phase at the 7-8th day of life. As it was shown in the behavioural experiments, that is just the period of maximum generalized reaction to nociceptive stimulation. It was found that to this age, the surface of neurones in the complex significantly increases, their density remaining still high. The data obtained are discussed in relation to factors which account for ontogenetic changes in electrophysiological correlates of neuronal responses in the parafascicular complex to peripheral nociceptive stimulation.     

N-Methyl-D-Aspartate receptors in acquisition of the short-term memory in the honeybeeApis mellifera

Role of NMDA receptors in the process of associative learning has been studied in the honeybeeApis mellifera L. in behavior experiments, using method of conditional reflexes. To determine pharmacological profile of NMDA receptors, effects of Mg²⁺ ions, NMDA, glycine (Gly), antagonist of the glycine site 5,7-dichlorokynurenic acid (DCK), competitive antagonists of NMDA receptors: D,L-2-aminophosphovalerate (APV), L-2-aminophosphobutyrate (APB), and D-glutamyl-aminomethylphosphonic acid (GAMP) as well of antagonists of NMDA receptor ion channels MK-801 and ketamine (Ket) were studied on acquisition of alimentary conditional reflex and its retention in memory. NMDA increased capacity for learning by stimulating shortterm memory. The NMDA receptor co-agonist Gly activated this NMDA effect. DCK eliminated the NMDA and Gly stimulatoty effects. All tested antagonists at millimolar concentrations inhibited associative function. The data obtained confirm our hypothesis about participation of NMDA receptors in processes of formation of short-term memory in the honeybeeApis mellifera and suggest that functional characteristics of the NMDA receptors involved in the process of associative learning in the honeybee resemble those in mammals.     

Increased affinity of liposomes derived from total spleen and liver lipids to spleen cells

The interaction of liposomes derived from total lipids of mouse spleen and liver with mouse spleen cells was studied. It was shown that the binding of these liposomes is much higher than the binding of liposomes obtained from a model lipid mixture--phosphatidylcholine--phosphatidylethanolamine--cholesterol (2:1:1). Adherent and nonadherent spleen cells were found to have affinity for liposomes derived from total lipids of spleen or liver. Removal of gangliosides and protein contaminants from the liposomes derived from total spleen lipids caused an increased binding of liposomes to spleen cells. Multilamellar liposomes bound more effectively to ultrasonicated vesicles having a homologous lipid composition than the liposomes with a different lipid composition. The increased affinity of liposomes derived from total lipids of spleen or liver for spleen cells may account for the identical fluidity of the lipid bilayer of liposomes and plasma membranes of spleen cells.     

A decrease in the content of immunoreactive alpha- and gamma-endorphins in the blood and the suppression of their hypersecretion under the influence of dexamethasone in emotional stress in monkeys

Daily administration of 12 mg of dexamethasone to monkeys during 10 days resulted in decrease of the levels of alpha- and gamma-endorphins and cortisol 7 days after the first injection. The titers of these peptides in plasma of monkeys. exposed to two hours of immobilization stress were elevated twice above basal levels. The maximum elevation took place 6 hours after the beginning of immobilization. This effect wasn't detected in monkeys, which received 12 mg of dexamethasone during 10 days.     

Structural features of the brains of rats selected for their thresholds of neuromuscular excitability

As a result of selection of rats possessing a high threshold of neuro-muscular exitability in comparison with rats possessing a low threshold of neuro-muscular exitability, certain changes take place in the structures that are connected with the learning process: the visual cortex is wider, volumes of the pyramidal cells in the fields CA1 and CA3 of the hippocampus are increased, density of the glial elements in the fornix is essentially increased and that of neurons in the septal nucleus is decreased.     

Assessment of Caspian Seal By-Catch in an Illegal Fishery Using an Interview-Based Approach

The Caspian seal (Pusa caspica) has declined by more than 90% since 1900 and is listed as endangered by IUCN. We made the first quantitative assessment of Caspian seal by-catch mortality in fisheries in the north Caspian Sea by conducting semi-structured interviews in fishing communities along the coasts of Russia (Kalmykia, Dagestan), Kazakhstan and Turkmenistan. We recorded a documented minimum by-catch of 1,215 seals in the survey sample, for the 2008–2009 fishing season, 93% of which occurred in illegal sturgeon fisheries. Due to the illegal nature of the fishery, accurately quantifying total fishing effort is problematic and the survey sample could reflect less than 10% of poaching activity in the north Caspian Sea. Therefore total annual by-catch may be significantly greater than the minimum documented by the survey. The presence of high by-catch rates was supported independently by evidence of net entanglement from seal carcasses, during a mass stranding on the Kazakh coast in May 2009, where 30 of 312 carcasses were entangled in large mesh sturgeon net remnants. The documented minimum by-catch may account for 5 to 19% of annual pup production. Sturgeon poaching therefore not only represents a serious threat to Caspian sturgeon populations, but may also be having broader impacts on the Caspian Sea ecosystem by contributing to a decline in one of the ecosystem’s key predators. This study demonstrates the utility of interview-based approaches in providing rapid assessments of by-catch in illegal small-scale fisheries, which are not amenable to study by other methods.     

Lipid peroxidation in experimental Salmonella infection

The results of investigation of lipid peroxidation in experimental Salmonella infection in 21-day-old rabbits are analyzed. Salmonella infection was accompanied by activation of lipid peroxidation not only in enterocytes, but also in blood serum. An increase in the level of malonic dialdehyde leads to a decrease in the antioxidation capacity and in the peroxidation resistance of erythrocytic membranes. The severity of the pathological process was found related to the activity of lipid peroxidation.