[Comparative study of behavioral effects of cortexin and cerebrolysine upon intraventricular and intraperitoneal administration in rats].

The comparative central effects of polypeptide drugs cortexin and cerebrolysin were studied in Wistar rats after introduction into the cerebral ventriculi in a dose range from 1 mg to 10 mg and 100 mg and after intraperitoneal injections in a dose of 1 mg/kg. Both drugs produced a moderate psychostimulant action, cortexin being more effective as compared to cerebrolysin. This effect was confirmed by all methods studied, including open field, elevated plus-maze, intruder-resident, and self-stimulation of the lateral hypothalamus. It is suggested that cortexin and cerebrolysin have similar mode of action, while cortexin is more effective than cerebrolysin. A difference between the intraventricular and intraperitoneal effects of drugs was that in the first case both drugs produced a moderate anxiolytic action, while in the second case an anxiogenic effect was registered. The central anxiolytic effect of drugs is probably related to a nonspecific action of polypeptides administered via brain ventriculi.

[Effect of peptides introduced into the central nucleus of amygdala on the hypothalamic self-stimulation in chronically alcoholized rats].

The reinforcing properties of neuropeptides (substance P, corticoliberin, leu-enkephalin, alaptide) and 70 kDa heat shock protein (HSP) administered into the extended amygdala were studied on the hypothalamic self-stimulation model in rats reared in community or social isolation since the 17th day after birth. Since that time (17th day) half of rats were given 5 - 15 % ethanol solution instead of water (semiforced alcoholization). In the age of 90 - 100 days, all rats were implanted electrodes into lateral hypothalamus and cannulas into the central nucleus of amygdala. In the group of alcohol-dependent rats, the alcohol administration was continued. In rats reared in community, corticoliberin, leu-enkephalin and substance P increased the reinforcing properties of self-stimulation in dose-dependent manner, but alaptide and HSP decreased self-stimulation moderately. In rats reared in social isolation, the vector of neuropeptide effects was retained, although the magnitude of the effects was lower. Therefore, the neuropeptides differently participate in the reinforcing mechanisms of hypothalamus. It is suggested that the extended amygdala modulates the reinforcing properties of lateral hypothalamus, probably by means of extrahypothalamic corticoliberin-containing neurons.

Self-consistent turbulence in the two-dimensional nonlinear Schrödinger equation with a repulsive potential.

The dynamics of dark solitons (vortices) with the same topological charge (vorticity) in the two-dimensional nonlinear Schrödinger (NLS) equation in a defocusing medium is studied. The dynamics differ from those in incompressible media due to the possibility of energy and angular momentum radiation. The problem of the breakup of a multicharged dark soliton, which is a local decrease of the wave function intensity, into a number of chaotically moving vortices with single charge, is studied both analytically and numerically. After an initial period of intensive wave radiation, there emerges a nonuniform, steady turbulent self-organized motion of these vortices which is restricted in space by the size of the potential well of the initial multicharged dark soliton. Separate orbits of finite widths arise in this turbulent motion. That is, the statistical probability to observe a vortex in a given point has maxima near certain points (orbit positions). In spite of the fact that numerical calculations were performed in a finite region, the turbulent distributions of the vortices do not depend on the size of the container when its radius is larger than the size of the potential well of the primary multicharged dark soliton. The steady turbulent distribution of vortices on these orbits can be obtained as the extremal of the Lyapunov functional of the NLS equation, and obeys some simple rules. The first is the absence of Cherenkov resonance with linear (sound) waves. The second is the condition of a potential energy maximum in the region of vortex motion. These conditions give an approximately equidistant disposition of orbits of the same number of vortices on each orbit, which corresponds to a constant rotating velocity. The magnitude of this velocity is mainly determined by the sound velocity. An integral estimation of the self-consistent rotation of the vortex zone is given.