Changes in the functional state of spinal-cord cell structures under gravitational unloading

The functional properties of the spinal-cord structures of experimental rats under a 7-day gravitational unloading were assessed using the method of transcranial magnetic stimulation. Hypogravity was modeled by hanging the animals by their tails in an antiorthostatic position. The gastrocnemius muscle potentials evoked by magnetic stimulation of the efferent structures of the spinal cord were registered. We found that gravitational unloading causes significant changes in motor-potential parameters and the central motor transmission time. We propose that the cause of the revealed transformations is afferent inflow limitation, first of all the motor type, as well as adaptation of the central nervous system to new conditions of motor activity.     

Bioelectric activity and metabolism of individual brain structures at different times after administration of synthetic tetrapeptidamide

Complex study of the opioid tetrapeptide amid (TPA) effect on metabolism and neurophysiological processes of different cortical areas, caudate nucleus n. accumbens allowed to detect prolonged (several days) specific action on these structures. The influence was manifested in certain changes of transmitter metabolism, background bioelectric activity, as well as in changes of EEG reactions to adequate afferent signals. The duration of the detected changes significantly exceeded the duration of anti-pain TPA effect.     

Changes in the activity of the brain renin-angiotensin system and in the functional state of the pituitary-adrenal system of rats under the influence of captopril]

While studying the effect of peroral captopril injections on the activity of renin-angiotensin system (RAS), the activity of angiotensin-converting enzyme (ACE) and angiotensin II content from anterior and mediobasal hypothalamus, medulla and adenohypophysis of intact rats has been established to decrease. Captopril administration decreases ACE activity which increases after hydrocortisone injection in rat medulla and striatum. Captopril results in no potentiation of hormonal effect in hypothalamus and in adenohypophysis where ACE activity decreases following hydrocortisone injection. A decrease in the RAS activity of brain structures and adenohypophysis induced by captopril administration to rats is accompanied by the inhibition of the activity in the pituitary-adrenal system. A decrease in ACTH level and in 11-hydroxycorticosteroids of the rat blood plasma has been determined after single captopril injection in the dosage of 10 and 50 mg/kg of body weight. Duration of the effect depends on the captopril dosage.     

The functional asymmetry of the limbic structures of the brain]

The recent evidence from literature testify to functional asymmetry of the structures belonging to the limbic system: hippocampus, amygdala, and hypothalamus. Predominant activation of the right hippocampus and right amygdala during perception and memorizing of visual picturesque images and solving the tasks provoking emotional stress, apparently, concerns the functional specialization of the right hemisphere in general. The leading role of the left hypothalamus in provocation of food, sexual, and defensive responses was experimentally verified. This finding is in line with the functional role of the left hemisphere in genesis of motivational states.     

Changes in collagen structure under the influence of mechanical dispersion

Air-dry collagen isolated from cattle retinal layer by means of alkaline-salt treatment was crushed in a laboratory vibro-mill at 80-150 degrees K. Mechanochemical transformations were studied by means of viscosimetry, polarimetry, ESR-spectroscopy and electron microscopy. Mechanical tensions induce breakage of covalent bonds of polypeptide chains, accompanied by a decrease of protein molecular mass, and of lateral interactions, which results in loosening of collagen structure and partial denaturation.     

The presence of enkephalin-like substances in the eyestalk and brain of the land crabGecarcinus lateralis

The eyestalk of the land crab, Gecarcinus lateralis, is rich in Met-enkephalin-like materials. Leu-enkephalin, if present, is at a level which is below the sensitivity of our assay. The brain (cerebral ganglion) of this organism contains both Met- and Leu-enkephalin-like materials. Material which was reactive with our Met-enkephalin antibody was also detected in a peak that migrated after Leu-enkephalin. This biochemical study confirms earlier immunohistochemical reports which indicated that opioid substances are present in crustaceans. It also strongly supports the concept that opioid mechanisms are a product of early evolution and further demonstrates that the sequence of the smaller opioid compounds has been conserved.     

Changes in the functional activity of macrophages, their morphology and metabolism under the influence of several biologically active substances]

The functional activites of peritoneal macrophages, their morphology and metabolism under the effects of some metabolic inhibitors and various biological ngents were studied. A correlation between functions of macrophages (speading on glass, pinoctosis of virus particles), changes in their metabolism (RNA and protein synthesis; specific activity ofcreatinkinase and catepsin), properties of the macrophages plasma membrane, and the number of lysosomes, was found.