Effect of hypokinesia and physical loading on the ultrastructure of cardiac myocytes

The experiments were carried out in rabbits and rats during 1--7.5 months. They demonstrated increasing disturbances in ultrastructure of the protein synthesizing myocardiocyte apparatus. The major and most dangerous disorder is the deficiency in the myocardial apparatus, which is, evidently, the main cause in the reduction of the cardiac functional reserves. Externally, similar reaction of the organism in response to loading (treadmill)--deep fatigue--produces diverse ultrastructural changes in the myocardium depending on the initial adaptive level to motor activity. In rabbits, having satisfactory adaptation to motor activity, the loading (treadmill) results, mainly, in exhaustion of their energy storage. In disadapted animals it produces dangerous lesions in the contractile apparatus of the cardial myocytes.     

Effect of prolonged hypokinesia on the growth and skeletal musculature in the rat

Hypokinesia lasting for 1-5.5 months does not produce any muscular atrophy, but results in ceasing their growth and the growth of the animal. In the muscles, besides the soleus muscle, not any essential structural changes occur. The changes in the soleus muscle are manifested as a focal sclerosis and formation of new muscle fibers. They are considered as a result of a disturbed hemodynamics in it, that occurs during the first days of hypokinesia. During the readaptation period the animals and their muscles begin to grow again. A suggestion is expressed that one of the pathogenic causes making the growth stop is the stress that decreases the somatotrophic function of the hypophysis.     

Influence of delta-sleep-inducing peptide on the activity of proteolytic enzymes in the rat brain under hypokinesia]

Single administration of the delta-sleep-inducing peptide (DSIP) in a dose of 12 micrograms/100 g to intact animals makes the activity of neutral proteinases and cathepsin D higher in the rat brain and blood serum. Hypokinesia of different duration changes activity of neutral and acidic proteinases and induces accessibility of cathepsin D to the cytosol as a result of damage in lysosomal membrane. Injection DSIP induces a decrease A/B of cathepsin D to the control level under 1-h hypokinesia condition and normalizes the neutral proteolytic activity under 6-h hypokinesia condition.     

Effect of adafenoxate on different rat brain structures monoamine oxidase activity in vitro

1. The effect of the nootropic drug adafenoxate on monoamine oxidase (MAO) activity in rat brain cortex, striatum, hypothalamus and hippocampus has been studied using the following substrates: tyramine (total MAO), serotonin (MAO A) and beta-phenylethylamine (MAO B). 2. In a series of increased concentrations (from 5 x 10(-4) up to 1 x 10(-5) M) adafenoxate inhibits total MAO, MAO A and MAO B in the brain structures studied. 3. The adafenoxate IC50 values obtained illustrate its inhibitory properties and its lack of selectivity toward MAO in the brain structures isolated. 4. The results of our research prove the participation of MAO in the mechanisms through which adafenoxate affects the brain monoaminergic systems and realises its central effects.     

Effect of gossypol on the ultrastructure of rat spermatozoa

Summary Gossypol was found to induce sterility in male rats when administered orally. A reduction in the number of spermatozoa in the epididymis from the gossypol-treated rats was observed when compared to the control animals. An examination of the spermatozoa from the treated rats showed the following ultrastructural modifications: disorganization of the mitochondrial sheath and missing cell membrane from the middle piece, broken cell membrane and missing members of both outer fibers and inner microtubules of the principal piece, and broken cell membrane of the sperm head. Serial mating experiments proved that gossypol-treated males were indeed sterile. The results suggest that gossypol at low concentrations is able to affect the motility of spermatozoa, thus contributing to its contraceptive action.     

Effect of social isolation on the ultrastructure of the dog brain

Ultrastructural changes in the central nucleus of the amygdalar body, field CA I of the hippocampus, piriform cortex, field 17 and field 7 have been studied in dogs, bred under conditions of social isolation. The changes are more numerous in emotiogenic structures. Similar ultrastructural rearrangements are revealed in the amygdalar body, hippocampus and in both fields of the neocortex. They are: neurons with different degree of chromatolysis, reactive changes in some organelles, terminals with agglutinated vesicles, or with their reduced number, increasing amount of synapses with a short active zone. At the same time, in the piriform gyrus vacuoles, membrane-like and osmiophilic inclusions, terminals with granular vesicles of various size are found more often.     

Effect of neurotransplantation on the content of catecholamines in the rat brain structures after heavy craniocerebral trauma

It was found that heavy craniocerebral trauma (CCT) in rats results in a drop in the dopamine and noradrenaline content in the damaged cerebral hemisphere, striatum, and hypothalamus. Transplantation of embryonic neural tissue after CCT in rats favors restoration of the level of catecholamines. Thirty days after the transplantation, the level of noradrenaline and dopamine in damaged structures mentioned above becomes similar to that in intact animals, or exhibits a tendency to be restored.     

Effect of angiotensin on the ultrastructure of the rat thyroid gland

Four hours after administering angiotensin to rats accumulation of radioactive iodine by the thyroid glands is inhibited. Angiotensin produces the contraction of thyroid arterioles. The cytoplasm of endotheliocytes of the perifollicular exchange microvessels becomes dense and luminar surfaces very involuted. Administration of angiotensin also leads to the changes in the ultrastructure of thyrocytes. The cisternae of the granular endoplasmic network get enlarged, the number of membrane-associated ribosome and mitochondria diminishes, that of lysosomes increases.     

Effect of postganglionic sympathectomy on the ultrastructure of the rat parotid gland

Summary Following two weeks of superior cervical ganglionectomy, the parotid glands of adult rats were removed and studied by electron microscopy. Sympathectomy induced striking alterations of acini, resulting in a heterogeneous population of acinar cells, but it had no obvious effect on the duct system. Most of the altered cells could be classified on a cytological basis as dark cells or light cells. Dark cells predominated and contained more secretory granules, less granular endoplasmic reticulum, fewer Golgi membranes, and smaller lumina and intercellular canaliculi than normal acinar cells. The synthesis and extrusion of secretory products appeared to be minimal in these cells. Light cells possessed ultrastructural features, such as dilated cisternae of granular endoplasmic reticulum and prominent Golgi membranes, which were opposite to those of dark cells and indicative of a high degree of secretory activity.The heterogeneous population of cells following sympathectomy indicates that the sympathetic nervous system may play an important role in regulating the secretory synchrony of acinar cells.Supported by U.S.P.H.S. Grant DE 02110.     

Effect of tranylcypromine on glycogenolysis in the rat brain

In rat brain the tranylcypromine administration induces after two hours a 151% increase of serotonin levels and a 50% fall of glycogen concentration. The activity of phosphorylase a and b and the glycolytic flow rate are unchanged.     

Effect of a varying corticosteroid allowance on the cAMP content of limbic system structures of the rat brain

A study was made of the effect of adrenalectomy and substitution therapy in the absence of adrenals on the cAMP content in the hypothalamus, hippocamp and striate body of the rat brain. It was shown that in sham adrenalectomized animals, the concentration of cAMP in the brain structures under study did not differ from the characteristics recorded in the control group. Adrenalectomy in rats was followed by a significant reduction of the nucleotide in all the structures, namely in the hypothalamus by 89.5%, and in the hippocamp and striate body by 30.3 and 30.5%, respectively. Application of substitution therapy (5 mg hydrocortisone per 100 mg body mass) prevented the decreased content of cAMP seen in the adrenalectomized rats, with its magnitude being within the limits recorded in the intact animals. Doca was little effective in this aspect.     

Muscle electrolyte measurements during and after hypokinesia in determining muscle electrolyte depletion during hypokinesia in the rat

Hypokinesia (diminished movement) induces muscle mineral depletion. However, the mechanism of muscle mineral depletion during hypokinesia (HK) remains unknown. Measuring electrolyte retention and electrolyte values in muscle, plasma, and urine during and after HK, the aim of this study was to discover if HK could depress mineral retention and lead to muscle mineral depletion. Studies were done on 204 13-wk-old male Wistar rats (370–390 g) during 10 d pre-HK period, 98 d HK period, and 15 d post-HK period. Rats were equally divided into two groups: vivarium control rats (VCR) and hypokinetic rats (HKR). All hypokinetic rats were kept for 98 d in small individual cages, which restricted their movements in all directions without hindering food and water intakes. All control rats were housed for 98 d in individual cages under vivarium control conditions. Both groups of rats were pair-fed. During the HK period skeletal muscle sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), and water content and electrolyte retention decreased significantly (p < 0.05), while urinary and plasma electrolyte levels increased significantly (p < 0.05) in HKR compared with their pre-HK values and their respective VCR. During the initial days of the post-HK period, mineral retention increased significantly (p < 0.05), plasma and urinary electrolyte level decreased significantly (p < 0.05), while muscle electrolyte and water content remained significantly (p < 0.05) depressed in HKR compared with VCR. Muscle mineral and water content, electrolyte retention, plasma, and urinary electrolyte values did not change in VCR compared with their pre-HK values. It was concluded that during HK decreased muscle mineral content may suggest muscle mineral depletion, while increased urinary electrolyte loss and muscle mineral depletion may demonstrate reduced mineral retention. Reduced electrolyte excretion and depressed muscle mineral content during post-HK may indicate skeletal muscle mineral depletion during HK. Dissociation between electrolyte retention and muscle mineral depletion may demonstrate the presence of decreased electrolyte retention as the mechanism of muscle electrolyte depletion during prolonged HK.     

Effect of adenosine on cyclic nucleotide levels in brain structures

Adenosine influence on cAMP and cGMP levels in cortex, hypothalamus, hippocampus and cerebellum was studied. It was established that adenosine and inhibitor of its reuptake--dipyridamole change cyclic nucleotide levels in some structures of brain (intraperitoneal injection). It was shown that cAMP and cGMP were in reciprocal relations in cortex, but not in hypothalamus, hippocampus and cerebellum.