Vol 11, No 3 (2013)

The review devoted to neurobiological mechanisms of both positive and negative reinforcement is represented. The key role in these processes plays the nucleus accumbens as a part of the extended amygdala system. The afferent and efferent connections of the n.accumbens, starting mechanisms of the n.accumbens involvement in emotional reactions, interactions between n.accumbens and other structures of the extended amygdala system, and neurochemical organization of the n.accumbens and all system of reinforcement are discussed in the article. The special attention is taken to the n.accumbens participation in addictive behavior.

The changes in transmembrane calcium, sodium and potassium ionic currents after extracellular administration of dibazol (2-(phenylmethyl)-1H-benzimidazol hydrochloride) and its two new derivatives in concentrations of 1, 10, 100 and 1000 µM were studied by the method of intracellular dialysis and fixation of membrane potential in isolated neurons of the Lymnaea stagnalis mollusk. Dibazol in concentrations of 1 and 10 µM effected slightly on the ionic currents. High concentrations of dibazol (100 and 1000 µM) inhibited all currents in dose dependent manner with maximal effect on potassium currents amplitude. ЕС50 were 7.4 мМ for INa, 4.0 мМ for ICa, 83.9 µM for IKs,1 (one group of neurons) and 2.9 мМ for IKs,2 (the another group of neurons). The voltage-amper membrane characteristics shift was not registered, but the kinetics of currents development was changed. Dibazol was more effective in inhibition of ionic currents compared to its structural analogs.

The study wThe left ventricular end diastolic pressure (EDP) fluctuations, specific peripheral vascular resistance (SPR) and cardiointervals (RR) on the respiration frequency under hard normobaric hypoxia (FIO2 = 0.1) were studied. 7 young men (volunteers) were subject to series of hard hypoxic exposures (6 weeks, every other day, intermittently by 6 × 5 min – FIO2 = 0.1). The hypoxic tests (HT1 and HT2) – FIO2 = 0.1, 15 min continuously) were performed before and after each series. SаO2 at the last 3 m of the tests on average was 82.5 % and 92.0 % respectively (Р < 0.05). During HT1 and HT2 (in comparison with inactivity) were increased: angle of max QRS vector (VQRS) in the frontal plain (68.5° ± 16.68 and 72.94° ± 15.32; 69.62° ± 22.4 and 74.45° ± 17.98 respectively), minutes blood flow (MBF) (6.41 ± 1.98 l/min and 6.87 ± 1.27 l/min; 5,27 ± 1,02 l/min and 5.67 ± 1.19 l/min respectively) (Р < 0.05). SPR was decreased too (27.39 ± 5.45 s.u. and 25.62 ± 4.96 s.u.; 30.59 ± 6.34 s.u. and 27.93 ± 5.77 s.u. respectively) (Р < 0.05). By means of transfer function analysis was shown that EDP fluctuations at HT2 significantly outpace by time (phase) the SPR and RR fluctuations on the respiration frequency (1.19 s ± 0.64 and 1.99 s ± 0.63 or 94.39° ± 43.3 and 125.4° ± 7.54; 1.65 s ± 1.28 and 2.22 s ± 0.87 or 101.4° ± 59.6 and 152.7° ± 21.26 respectively) (Р < 0.05). The increased oxyhemoglobin saturation is a trigger of artery wall smooth muscle relaxation mechanisms and this one is changes the background for beat to beat baroreflex realization on the respiration frequency.

The present work is devoted to the study of the peptides bioregulators of new generation (Cortexin, Semax, Selank) in the compensation of the disturbed Higher Nervous Functions ih the ascending row of mammls (insectivores, rodents, primates). The new data have been established that at the early stage of mammals (in insectivores) Cortexin, Semax and Selank induced the more significant and long lasted effect on inherent forms of behaviour. Their effects on the compensation of the disturbed Higher Nervous Functions have nonspecific, facilatory short time lasted character. Contrary to insectivores, rodents have a clear tendency to compesation for Higher Nervous Function disturbances. At the Semax and Selank background, the delayed conditional reflexes were restored. It has been established that the cerebroprotective effects of Selank exerted more significant influences upon the brain function disturbances in neurotic rats. Contrary to the results found in lower mammals, the application of Cortexin, Semax and Selank to neurotic monkeys exerted differnt effects upon the Higher Nervous Functions disturbances. The compensatory effects of drugs are dose dependant in nature being more effective with intranasal administration and having different effects on the various types of neurosis. The long duration compensation of the mental disturbances (the EEG homeostatic parameters of memory processes) took place during the Selank (30 mkg/ kg) administration. The cerebroprotective effects of Semax are especially significant on the operative memory. Cortexin antiamnestic and cerebroprotective effects especially significant at the inhibitory type of neurosis. The data collected on the compensatory Cortexin, Semax and Selank influeces on the disturbed memory processes and cognitive deficit of monkey’s may serve as neurophysiological basis for the more intensive and specific role of these drugs in the neurological clibic.