Decrease in the cytogenetic effect of adriblastin and pharmorubicin with the experimental use of tularemia vaccine

Immunization of Wistar rats with tularemic vaccine has been studied for its influence on the cytogenetic effect of adryblastine and pharmorubicyn. It is shown that the number of aberrant metaphases considerably decreases in the myelocaryocytes of vaccinated rats. Antimutagenic effect is induced by the influence of tularemic vaccine on the metabolic activation processes of antibiotics and, possibly, by an increase of the activity of antioxidative enzymes in the rat organism.     

The influence of actinomycin D on the activity of delta-aminolaevulinic acid synthetase and dehydratase in the liver of mice and rats treated by griseofulvin.

The changes of delta-aminolaevulinic acid dehydratase--the second enzyme of porphyrin synthesis--were studied and compared in the liver of mice and rats treated with griseofulvin. The results showed that griseofulvin increased the activity of delta-aminolaevulinic acid dehydratase in the liver of mice and rats treated by griseofulvin. No differences were found between mice and rats as to the effect of griseofulvin on the activity of delta-aminolaevulinic acid dehydratase. The influence of the administration of actinomycin D on the activity of delta-aminolaevulinic acid synthetase and dehydratase in the liver of mice and rats was studied at an early period of experimental porphyria induced by griseofulvin. It was found that the administration of actinomycin D blocked the observed effect of griseofulvin on the activity of both enzymes in the liver of mice and rats.     

Neurophysiological analysis of the role of emotional stress in formation of a morphine addiction

In chronic experiments on rats we studied the influence of emotional stress (sessions of nociceptive stimulation in a conflict situation applied during 15 days) on formation of a morphine dependence. The influence of individual sensitivity of rats to stressing on formation of qualitatively dissimilar reactions to morphinization is demonstrated. The rats resistive to stress appeared resistive to the morphine influence too;vice versa, the rats with a low resistivity to stressing demonstrated facilitated development of the morphine motivation. We conclude that such individual specificities of the reactions to morphinization are determined by the initial state of the functional activity of the emotiogenic brain system.     

Effects of antidepressive agents on tolerance of hypoxia and physical exercise]

In experiments on mice and rats we studied the influence of antidepressants on hypoxic and physical tolerance. The antidepressants pyrazidol, azaphen, imipramine and moclobemide as well as the nootropic drug piracetam prolonged the life of animals in conditions of hypoxic and hemic hypoxia and increased the survival rate of rats in circulatory hypoxia. In experiments on mice antidepressants increased also the time of swimming.     

Blood levels of corticosterone, aldosterone, angiotensin and ACTH in rats after deafferentation of the tongue

The influence of tongue deafferentation on the plasma level of sodium homeostasis-controlling hormones has been studied. Using radioimmunoassay, high corticosterone and aldosterone plasma levels were discovered in rats with tongue deafferentation, as compared to sham-operated controls. ACTH and angiotensin I plasma concentrations in deafferentated rats were the same as in sham-operated rats. The role of emotional factors of taste perception in sodium homeostasis control is being discussed.     

The action of tropic adenohypophyseal hormones when administered intraventricularly on rat behavioral reactions

In experiments on rats the influence was studied of tropic hormones of adenohypophysis--somatotropin, thyrotropin and adrenocorticotropin (STH, ThTN and ACTH respectively) on the elaboration and extinction of conditioned reaction of active avoidance (CRAA) in Y-maze and behaviour in the open field under microinjections of hormones into the brain lateral ventricle (0.001-0.002 ME). It has been shown that all studied hormones improve animals learning at negative pain reinforcement; ThTH and ACTH retard it in contrast to STH, which accelerates the extinction of the elaborated CRAA; tropic hormones exert differentiated influence on rats behaviour in the open field. No distinct correlation was found between behavioural manifestation and the level of catecholamines in the rats hypothalamus.     

Morphological and enzymological changes of small intestine of adult female rats and youngs born from madiol-treated pregnant rats

Some histological and histoenzymological changes of the small intestine of adult female Wistar rats treated with Madiol were studied. The steroid did not influence the tissular aspect, but obviously stimulatory effects on protein and enzyme reactions were induced. Similar Madiol-action on the small intestine of 21-day-old young rats was observed when the steroid was administered during pregnancy to their mothers, suggesting influences on the embryonic development.     

Potentiation of hypoglycemic response of glibenclamide by piroxicam in rats and humans.

Influence of piroxicam (PX) on glibenclamide (GL) induced hypoglycemia has been studied in rats, healthy human volunteers and diabetics. GL per se has significantly reduced blood sugar levels in rats and in humans. PX per se has significantly reduced BSLs, in diabetics, while having no significant influence on blood sugar level in rats and healthy human volunteers. Prior administration of PX has potentiated the hypoglycemic effect of GL in rats, healthy human volunteers and diabetics. GL, PX + GL administration have also significantly influenced the glucose tolerance test (GTT) in healthy human volunteers.     

Role of thyroid on testicular lipids in prepubertal, pubertal and adult rats. I. Hyperthyroidism

The influence of thyroxine-induced hyperthyroidism on testicular neutral and phospholipids was studied in prepubertal, pubertal and adult rats. Thyroxine treatment (25 micrograms/100 g body weight) for 1 month decreased testicular total lipids, total glyceride glycerols, total cholesterol and total phospholipids. Different classes of glyceride glycerol, cholesterol and phospholipid were also diminished due to thyroxine treatment. All classes of lipids returned to the euthyroid level after the withdrawal of thyroxine treatment. The data obtained in the present study suggest that thyroid hormones have a definite influence on testicular lipid metabolism in rats.     

Age-related characteristics of the effect of periodic low-calorie nutrition on lipid composition of the liver cells, small intestine, adipose tissue and blood serum in albino rats

It is studied how long-term periodical calorie-insufficient and growth-restraining nutrition promoting appreciable life prolongation in the Wistar-line albino rats influences the lipid metabolism. It is shown that diet has an essential influence on the levels of phospholipids, cholesterol, neutral lipids, fatty acids in different tissue cells. The age specificity is observed in all the studied tissue cells. The lipid composition of cells in aged rats with prolonged life is similar to that of young animals of control group.     

Disordered learning and sleep structure in rats with a cobalt-induced epileptogenic focus in the sensorimotor cortex

The influence of cobalt-induced epileptogenic foci in the somatosensory area of the cerebral cortex on sleep-wakefulness pattern has been studied in rats and the data obtained were compared with the learning ability of rats. It has been established that the formation of cobalt-induced epileptogenic foci may result in a decreased ability to learn that correlated with the selectivity of phasic components of the paradoxical sleep hippocampal theta-rhythm.     

Effect of thyroxine on the hepatic glycogen and glucose-6-phosphatase activity of developing rats

The influence of exogenous thyroxine was studied on the hepatic glycogen content and glucose-6-phosphatase activity of rats of different age groups. The glycogen content and glucose-6-phosphatase activity were found to be decreased in the livers of 5, 15, 30 and 60-day-old rats after thyroxine treatment. In normal rats of 5, 15, 30 and 60-day-old, a gradual rise in both the hepatic glycogen content and glucose-6-phosphatase activity was noted as the age advanced from immature to adult.     

Formation of alcohol motivation under blockade of protein synthesis by cycloheximide]

The influence of protein blocker cycloheximide on ethanol intake in rats under condition of development of alcohol motivation was studied. It was found that intracerebroventricular injection of cycloheximide caused inhibition of alcohol intake in rats which had free choice between water and 20% ethanol solution. The blockade action of cycloheximide on the development of alcohol motivation was dependent on initial preference of ethanol in rats and was more strong in rats with originally low preference for ethanol.     

Studies on L-arginase in developing rat small intestine, brain, and kidney. II. Effect of hydrocortisone and thyroxine

The influences of hydrocortisone and thyroxine on the developmental changes of arginase activity in intestine, kidney, and brain of suckling rats were studied. A single injection of hydrocortisone (50 mg/kg) into rats aged 9 days evoked premature increase of jejunal arginase activity due to precocious formation of arginase A4. Arginase A4 can be detected about 48 hr after hydrocortisone injection, whereas in intact rats the enzyme appears in the intestinal mucosa on the 19th-21st days of postnatal life. After hydrocortisone administration to rats aged 6 days, a similar pattern of arginase activity in jejunum was observed. Under the same conditions, the influence of hydrocortisone on kidney arginase was weaker. The hormone did not have any influence on the activity of brain arginase. Daily injection of thyroxine (2 mg/kg) to 6-day-old rats (for 6 consecutive days) caused a precocious increase of the arginase activity in intestine. Under the same conditions, only a slight increase of the arginase activity was observed in kidney, whereas in brain the activity was unaffected.     

Implications of interscapular brown adipose tissue removal and sucrose overfeeding on the sympatho-adrenal activity and metabolic responses

1. The influence of sucrose overfeeding on the sympatho-adrenal (SA) and metabolic responses was studied in sham-operated (SHAM) rats and in those with interscapular brown adipose tissue (IBAT) removed. 2. Sucrose feeding significantly increased the SA activity, mobilized the free fatty acids (FFA), but did not change glucose homeostasis in sham-operated rats. 3. IBAT removal in control rats fed a stock diet modified the SA activity whereas the levels of both blood glucose and serum FFA were unchanged. 4. However, sucrose in rats void of IBAT potentiated the activity of sympathetic nervous system only and prevented the FFA rise, which is seen in sham-operated sucrose fed rats indicating that the enhanced level of serum FFA in these animals principally originated from the IBAT.     

Deficits in reproductive behaviour in septally lesioned female rats

Estrous cycle and sexual behaviour were studied in septally lesioned female albino Wistar rats. In lesioned rats the vaginal smears showed continuous diestrus and the females failed to exhibit sexual receptivity during the postoperative period. Ovarian and uterine weights in lesioned rats were also significantly decreased. The results suggest that the septal nuclei exert a modulatory influence on female sexual behaviour.     

Expression of the immediate-early gene cFos in brain of the rats exposed to repeated 2 G influence

Early gene c-Fos expression was studied by means of c-Fos protein immunostaining in brain locus coeruleus (LC) of the rats exposed to primary and repeated hypergravity. One-hour 2 G influence on rats induced in LC cells expression of c-Fos protein, pointing out early gene c-Fos expression and synaptic activation of LC neurons. After repeated 1-hour 2 G, postponed for 35 days after primary 30-day 2 G influence, expression of c-Fos protein in LC neurons was not found. This fact is considered as a sign of memorizing of primary hypergravity influence.     

Relations between anxiolytic effects of diazepam and changes in the EEG spectral power

The influence of diazepam (1; 5; 10 mg/kg, i. p.), chlorpromazine (1 mg/kg) and amphetamine (1; 5 mg/kg) on the Fourier's spectral EEG power of sensomotor cortex and dorsal hippocampus and conflict behavior freely moving albino and cotton (Sigmondon hispidus) rats was studied. Effects of diazepam (5 mg/kg) in cotton rats were similar, but influence on the theta-activity was more expressed. Correlation between slowing of theta-activity and extent of anxiolytic effect in conflict situation was showed. On the basis of the results obtained the authors discuss possible mutual relations between the influence of diazepam on EEG and anxiolytic effect of benzodiazepines.     

Effect of age and dietary restriction on protein synthesis by isolated kidney cells

The influence of age and food restriction on kidney protein synthesis was studied in Fischer F344 rats. The rate of total protein synthesis by suspensions of kidney cells declined 60% between 4 and 31 months of age. The rate of protein synthesis by kidney cells isolated from 19-month old rats fed a restricted diet (60% of diet consumed by rats fed ad libitum) was 45% higher than the rate of protein synthesis by kidney cells isolated from 19-month old rats fed ad libitum. The excretion of protein in the urine was measured to assess the effect of the age related decline in protein synthesis on kidney function. A dramatic increase in proteinuria was observed with increasing age, and rats fed the restricted diet excreted significantly less protein in the urine than rats fed ad libitum.     

Antioxidative enzymes in the liver and kidney of alloxan induced diabetic rats and their implications in cadmium toxicity

The influence of insulin-dependent diabetes mellitus on the oxidative stress caused by cadmium in the liver and kidney of laboratory rats has been studied. The results suggest that cadmium and alloxan diabetes independently promote lipid peroxidation in both liver and kidney. However, lipid peroxidation diminished in the diabetic rats fed cadmium. Administration of cadmium to normal and diabetic rats depleted glutathione in liver only. No significant change was observed in the activity of glutathione peroxidase in kidney, whereas administration of cadmium to diabetic rats stimulated catalase activity when compared to cadmium-fed rats. The actual mechanism of these effects still remains to be confirmed, but an antagonistic relationship between cytotoxic mechanisms of diabetes mellitus and cadmium is speculated upon. The insulin-dependent activity of a unique form of cytochrome 450j may be involved.