Effects of +Gz Loads on Structural Organization of Central Autonomic Nuclei.

Structural alterations in the central autonomic nuclei (dorsal vagal complex and intermediolateral nucleus) of the centrifuged random-bred male rats subjected to +Gz loads were examined. Acute exposure to gravitational loads predominantly produced the reactive changes in these nuclei, while persistently repeated regular loads resulted in cumulation of the destructive alterations. The structural perturbations in the central autonomic nuclei can disturb the autonomic regulation of physiological functions. The character of such disturbances is partially determined by the peculiarities in structural organization of these nuclei.

[ROLE OF THE SYMPATHOADRENOMEDULLARY SYSTEM IN FORMATION OF PILOT'S ADAPTATION TO FLIGHT LOADS].

Purpose of the work was to evaluate the sympathoadrenomedullary functions and associated psychophysiological reactions of pilots as a function of flight hours on highly maneuverable aircraft. Volunteers to the investigation were 78 pilots (41 pilots of maneuverable aircraft and 37 pilots of bombers and transporters). Selected methods were to enable comprehensive evaluation of the body functioning against flight loads. Our results evidence that piloting of high maneuverable aircraft but not of bombing and transporting aircrafts activates the sympathoadrenomedullary system significantly. This is particularly common to young pilots with the total flying time less than 1000 hours. Adaptive changes to flight factors were noted to develop with age and experience.

[Structural-functional reserves of the vegetative nervous system in pilots flying high maneuver aircrafts].

Purpose of the work was to analyze morbidity among pilots of different categories of aircraft, and to investigate reactivity of the vegetative nervous system (VNS) in pilots flying high maneuver aircrafts varying in age and flying time. Morbidity was deduced from the data of aviation medical exams. The VNS investigation involved 56 pilots of fighter and assault aircrafts both in the inter-flight periods and during duty shifts. Cytochemistry was used to measure glycogen in peripheral blood neutrophils in 77 pilots. It was shown that the pre-stress condition in pilots with the flying time more than 1000 hours may transform to chronic stress, provided that the flight duties remain heavy. According to the cytochemical data, concentration of neutrophilic glycogen indicating the energy potential of peripheral blood leukocytes is controlled by hormones secreted by the VNS sympathetic and parasympathetic components.

[Sympathetic and parasympathetic centers of the brain and spinal marrow of rats during exposure to +Gz].

Structural transformations in the dorsal vagal complex and intermediolateral nucleus due to +G, loads were studied in white outbred male rats centrifuged according to the standard procedure (P.S.Paschenko, 1995). Methods of investigation included light and electron microscopy, morphometric analysis and statistical analysis. Acute exposure to +Gz loads resulted in essentially reactive changes in the centers under study. At the same time, regular exposure to this extreme factor led to cumulation of destructive changes. The peculiar structure of the centers governs uniqueness of disorders which may unbalance the autonomous regulation of organism functions.

[The structural organization of the normal rat area postrema and under conditions of chronic exposure to gravitational loads]. / Strukturnaia organizatsiia area postrema krysy v norme i v usloviiakh khronicheskogo vozdeistviia gravitatsionnykh peregruzok.

Topography and structure of rat area postrema were specified using light optic and electron microscope. Disturbance of liquor-encephalic transport (hydrops of ependymocytes), sharp changes of cytoplasmic organelles in neurons, signs of intercellular desintergration (synapse degeneration after "clear" type), death of part of neurons, disorder in secretory processes in neuroendocrine cells were shown to occur following chronic effect of gravitation overloads, in its structural elements. These changes take place on the background of hemomicrocirculatory disturbances, appearance of connective tissue fibres in perivascular space of Virchow-Robin and are probably conditioned by a developing circulatory hypoxia.