Cytoangioarchitectonics of the parasympathetic ganglion of the frog bladder according to findings from studies during life]

The form of neuronal bodies and their interarrangement with capillaries was studied in prevital parasympathetic ganglia in the bladder of the frog (Rana temporaria). The size of the neurons and the diameter of the capillaries were measured. Most of the neurons were stated to have oval form and they are oriented by their long axis along the capillaries, about 20% neurons have contacts with 2--3 capillaries; some neurons have no contacts and their distance from the nearest capillary is 32--26 mkm. Intermediate structure may be either a connective tissue or neuroglia, or (seldom) other neuronal cells. Unequal conditions of neuronal blood supply, as the author believes, demonstrate their different metabolism and various levels of their functional activity.     

Adiabatically reduced magnetohydrodynamic equations for a cylindrical plasma with an anisotropic pressure

A closed set of reduced equations describing low-frequency nonlinear flute magnetohydrodynamic (MHD) convection and the resulting nondiffusive processes of particle and energy transport in a weakly collisional cylindrical plasma with an anisotropic pressure is derived. The Chew-Goldberger-Low anisotropic magnetohydrodynamics is used as the basic dynamic model, because this model is applicable to describing flute convection in a cylindrical plasma column even in the low-frequency limit. The reduced set of equations was derived using the method of adiabatic separation of fast and slow motions. It is shown that the structure of the adiabatic transformation and the corresponding velocity field are identical to those obtained earlier in the isotropic MHD model. However, the derived heat transfer equations differ drastically from the isotropic pressure model. In particular, they indicate a tendency toward maintaining different radial profiles of the longitudinal and transverse pressures.     

Fluorescent dyes as probes to study lipid-binding proteins

We studied the equilibrium binding of two hydrophobic fluorescent dyes, ANS and bisANS, to four members of a family of intracellular lipid-binding proteins: IFABP, CRABP I, CRABP II, and ILBP. The spectral and binding parameters for the probes bound to the proteins were determined. Typically, there was a single binding site on each protein for the ligands. However, IFABP cooperatively bound a second bisANS molecule in the binding pocket. Comparative analysis of affinities and spectral characteristics for the two probes allowed us to examine the contributions of electrostatic and hydrophobic interactions to the binding process, and to address some aspects of the internal structure of the studied proteins.     

Sleep changes during degeneration of neurons in the substantia nigra induced by inhibitor of proteasomes lactacystin in rats

A decrease in activity of ubiquitin proteasome system results in accumulation of toxic forms of protein and cell degeneration, including dopamine (DA)-ergic neurons in the substantia nigra; these neurons are remarkable for their low proteolytic activity of proteosomes that makes them more vulnerable, especially when subjected to the neurotoxin action or Parkinson's disease (PD). The goal of the present study is to develop a model on the basis of inhibition of proteasome activity of nigral cell degeneration which is not accompanied by disturbances in motor behavior but leads to changes in sleep-wake cycle characteristic of the non-motor behaviour. We determined the optimal dose of natural inhibitor of proteasome lactacystin (0.4 mkg) and developed a preclinical model of PD in Wistar rats. We established that on the 14th day following lactacystin double (with one-week interval) bilateral injection into the substantia nigra the developing effects involved 28 % degeneration of DA-ergic neurons in the compact part of the substantia nigra, absence of disorders in motor behaviour, and increase in the total time of rapid eye movement sleep by 37 % at the second half of inactive day phase. These data and an increase in the level of key enzyme of DA synthesis tyrosine hydroxylase (TH) in survived neurons in the substantia nigra as well as the presence of the inverse correlation dependency (r = -0.8, p < 0.01) between the number of survived neurons and the level of TH inside them suggest a hypothesis that the increase in the duration of rapid eye movement sleep could be a non-motor marker of the preclinical stage of PD reflecting a reservation of compensatory potentials in the nigrostriatal system.     

Content of chaperon Hsp70 in dopaminergic neurons of the black substance increases in proteasome dysfunstion

In Wistar rats, specific inhibitor UPS lactacystin induced degeneration of 24% of the dopaminergic neurons in the black substance. The work shows that a moderate weakening of the UPS function is characterized by an enhanced activity of the shaperon system. This process seems to restore and maintain population of the dopaminergic neurons.     

Participation of GABAergic Mechanisms of Hypothalamus Ventrolateral Preoptic Area in Regulation of Sleep and Wakefulness and Temperature Homeostasis in the Pigeon <Emphasis Type="Italic">Columba livia</Emphasis>

A comparative analysis of awakening, somnogenic, and thermoregulating effects of agonists and antagonists of GABAA,B-receptors after microinjections to neuronal populations of ventrolateral preoptic area (VLPA) of hypothalamus was carried out for the first time in representatives of the avian class (pigeon). It has bee established that: (1) VLPA of hypothalamus contains populations of neurons differing by their function and representation of receptor types and participating in control of wakefulness, sleep, and thermoregulation; (2) executive GABA_A-ergic mechanisms of maintenance of the slow-wave sleep (SWS) are located predominantly in the caudal part of the hypothalamic VLPA; (3) GABA_A,B-ergic mechanisms of control of thermal homeostasis are located predominantly in the caudal part of VLPA. It is suggested that the maintenance of SWS depends on an increase of activity of inhibitory GABAergic VLPA mechanisms leading to inactivation of neuronal networks of wakefulness outside VLPA and on a reduction of activity of the stimulatory aminergic systems present in the preoptic area and outside it.