Behavioral characteristics and protein synthesis in the brain of rats receiving ethanol with the mother's milk

The authors studied behavioral responses, conditioned reflexes and indices of protein synthesis in the structures of the brain in the progeny of female rats which received ethanol during the period of lactation.     

Aldehyde dehydrogenase activity and level of dopamine in certain sections of the brain of rats preferring and refusing ethanol

Aldehyde dehydrogenase activity (KF 1.2.1.3) of cytosol fractions of brain structures (hypothalamus, midbrain and new cortex) as well as dophamine content in these structures were studied in comparative aspect in rats preferring and rejection ethanol. It has been shown that there were two isoforms of aldehyde dehydrogenases (aldehyde dehydrogenase 1 and aldehyde dehydrogenase 2) in cytosol fractions of all investigated brain structures of animals preferring ethanol while only aldehyde dehydrogenase 2 has been found in the new cotex of rats rejecting ethanol. Thus, aldehyde-dehydrogenase activity is higher in the animals preferring ethanol than in those ones rejecting ethanol. Content of dophamine in the rats preferring ethanol is higher than in those ones rejecting ethanol both in the hypothalamus and new cortex. Differences between the studied groups of animals can underlie the pathologic attraction to alcohol.     

Behavioral characteristics of female Wag/Rij rats

Behavior of male and female WAG/Rij and Wistar rats was compared in the tests assessing the level of anxiety (light-dark choice, open field) and depression-like state (sucrose intake and preference, forced swimming). Females of WAG/Rij rats like males of the same strain exhibited symptoms of depression-like behavior: increased immobility in the forced swimming test and decreased sucrose intake and preference (anhedonia). In contrast to males, females of WAG/Rij rats displayed more distinct signs of increased anxiety as compared to Wistar rats. Both WAG/Rij and Wistar females exhibited increased locomotor and exploratory activity in the open field as compared to males.     

Electrolyte excretion in alcohol preferring and alcohol avoiding rats

Water and electrolyte metabolism was studied in alcohol preferring (AA) and alcohol avoiding (ANA) rats. During water diuresis AA rats had higher Mg, cAMP, creatinine and inorganic phosphate excretion, but lower urine and urinary protein output. During ethanol diuresis AA rats had lower Na, K, Ca, protein and urine output, but higher cAMP and inorganic phosphate excretion. Ethanol increased K, Ca and urine output in ANA rats only. A slight increase of blood pH was observed only in AA rats. Before ethanol ANA rats had higher plasma Ca concentration. Plasma aldosterone level was higher in AA rats. High salt excretion of ANA rats may lead them to prefer salt containing energy sources and therefore to avoid ethanol. On the other hand, renal salt conservation in AA rats may lead them to prefer ethanol.     

Chronic low dose ethanol intake: biochemical characterization of liver mitochondria in rats

Liver mitochondria were isolated from male rats exposed for 2 months to low doses of ethanol (3% v/v in drinking water), a condition not associated with tolerance or dependence. The results show no significant changes in the content of reduced or oxidized glutathione in the liver mitochondria of ethanol treated rats with respect to controls. However, a slight but significant increase in lipid peroxidation, accompanied by an increased content of oxidized proteins, was found in ethanol exposed animals. Mitochondrial content of cytochrome complexes was not significantly affected by ethanol intake. The specific enzymatic activity of cytochrome oxidase showed, however, a significant decrease in ethanol-treated rats. The slight mitochondrial alterations found in the liver of rats exposed chronically to low doses of ethanol might represent the beginning of a more extensive damage previously observed in rats exposed to high doses of this substance.     

Ultrastructural and biochemical characteristics of leydig cells from newborn androgen-insensitive rats

Summary Leydig cells of the testis of newborn pseudohermaphrodite (tfm) rats have an ultrastructure similar to that of the normal, containing well developed organelles and inclusions. The cytoplasm is filled with smooth endoplasmic reticulum forming a network of interconnected tubules. Lipid droplets are surrounded by cisternae of smooth endoplasmic reticulum and are in close association with pleomorphic mitochondria. Many of the latter are cup-shaped and have tubular cristae and intramitochondrial dense bodies.Essentially, these are characteristics of normal Leydig cells. Accordingly, the production of testosterone by testes from newborn tfm rats is the same as that by testes from normal newborns and adults. However, it is significantly higher than that by testes of tfm adults. Also, the plasma testosterone levels of newborn tfm rats are the same as in the normal newborn, but lower than in normal adults and much lower than in adult tfm animals.Thus, since in the tfm rat the morphology of Leydig cells, androgen production, and maintenance of plasma levels of testosterone are normal in the newborn, but become abnormal with advancing age, it appears that defective androgen action rather than insufficient androgen production is the cause of male pseudohermaphroditism.     

Hepatic lipids of intact or thyroidectomized rats after administration of tetracycline or ethanol]

The purpose of this work was to study the quantitative modifications of the hepatic lipids in adult thyroidectomized rats after administration of tetracycline or ethanol (acute dose or prolonged ingestion). 1. - Thyroidectomy did not inhibit the accumulation of fat in the liver of fed euthyroid or hypothyroid rats after intraperitoneal infusion of tetracycline (320 mg/body weight in 2 injections at an interval of 16 h, the diet containing 6% of lipids). 2. - Sixteen hours after the oral administration of a single large dose of ethanol (5 g/kg body weight), there were only found some small modifications of the lipid composition of the liver in fasting euthyroid or thyroidectomized rats, receiving a diet with 6% of lipids before the experiment; on the contrary, when the diet contained 19% of lipids, a fatty liver occurred in the intact rat, but not in the thyroidectomized rat. 3. - The prolonged ethanol intake (in a 20% solution in water) for 5 months with a diet containing 19% of lipids did not induce a fatty liver in intact rats but produced a decrease of hepatic non-phosphorus lipid and an increase of the cholesterol amounts. After the administration of L-thyroxin (10 mug/100 g body weight per day) to these alcoholic thyroidectomized rats during 2 weeks, it was found an increase of the hepatic non phosphorus lipids till an higher amount than in the euthyroid rats. 4. - The hepatic phospholipid amounts were relatively constant in the different experiments. These results accounting for this differential effects were discussed.     

Behavioral effects of L-tryptophan and p-chlorophenylalanine after adrenalectomy or dexamethasone administration in rats

Effects of acute administration of L-tryptophan (L-TRP. 250.0 mg/kg, i.p.) on active avoidance conditioning and "open-field" behavior were studied in male rats after adrenalectomy of dexamethasone administration. L-TRP inhibited the acquisition and reproduction of active avoidance reaction in adrenalectomized and dexamethasone-treated rats. Moreover, L-TRP decreased horizontal locomotor activity and grooming behavior in the "open field" on adrenalectomized rats. On the contrary, p-CPA restored the active avoidance conditioning in adrenalectomized rats and rats with excess of glucocorticoids. Also, p-CPA increased the total locomotor activity and grooming behavior in the "open field" in adrenalectomized rats, but decreased horizontal locomotor activity and enhanced emotional reaction in dexamethasone-treated rats in the "open field".     

Behavioral characteristics and stress reaction of the pituitary-adrenal system in prenatally stressed rats

Mothers' stress was shown to considerably diminish the orienting-studying activity of male rats in the dioestrus stage, as well as enhancement of anxiety. In prenatally stressed male rats, on the contraty, the anxiety diminished while their behaviour in the open field tests remained practically unaltered. The prenatal stress affected the stressor response of the hypophysis-adrenal systems in both sexes. The data obtained suggest that the mothers' stress affects both behaviour and stressor response in male as well as female rats.     

Hypotensive response of ethanol in rats pretreated with disulfiram or nitrefazole

The effect of disulfiram or nitrefazole pretreatment on ethanol induced hypotension was examined in urethane anesthetized rats. A relatively low dose of ethanol (150 mg/kg; i.p.) produced a characteristic hypotensive response in rats pretreated for various periods with disulfiram or nitrefazole. This hypotensive episode started 5-10 minutes following ethanol administration and lasted 40-60 minutes. The hypotensive response was not seen unless disulfiram or nitrefazole treatment preceded ethanol administration by a least 6-8 hours. The low dose of ethanol produced a plasma ethanol concentration of 10mg/100ml or less. One treatment with nitrefazole (200 mg/kg) rendered rats vulnerable to ethanol-induced hypotension for 6 but not 8 days. One treatment with disulfiram (200 mg/kg) lasted 4 but not 6 days. In addition, the hypotensive response was greater in rats treated with nitrefazole than in rats treated with an equal dose (200 mg/kg) of disulfiram.     

Correlation between the rate of ethanol elimination and the psychophysiological characteristics of rats

Ethanol elimination from the blood of rats with different psychophysiological features was studied using gas chromatographic head-space analysis in the general complex of tests aimed at determination of ethanol consumption. The selection of animals with different levels of the initial alcohol motivation was performed according to modified Porsolt's method. It was shown that the initial level of predisposition to depression-like states is in a dose-dependent correlation with the high rate of ethanol elimination. This is suggested to be one of the genetic indications which promotes the formation of the initial alcohol motivation and the development of experimental alcoholism.     

Plasma and liver amino acids in rats after administration of ethanol or acetaldehyde

The changes in the level and pattern of free amino acids in plasma and liver after ethanol or acetaldehyde intoxication has been investigated in rats. After administration of 30% (w/v) ethanol, 6 g kg-1, or 1.5% (w/v) acetaldehyde, 0.3 ml kg-1, for 4 weeks we found a decrease in plasma and liver branched-chain amino acids and an increase in plasma aromatic amino acids and methionine. The results are analogous to those found in studies of damaged liver.     

Dynamics of [2-14C]pyruvate incorporation into liver phospholipid fractions in rats consuming water or ethanol

The animals with preference to ethanol as compared to those with preference to water show an increase in the specific radioactivity of glycerol moiety of liver phosphatidylethanolamine 1 hour and in that of glycerol component of phosphatidylcholine 3 hours after the [2-14C]-pyruvate administration.     

Effect of ninhydrin on the biochemical and histopathological changes induced by ethanol in gastric mucosa of rats

Studies on the effect of ninhydrin in the normal gastric mucosa and against the ethanol induced gastric injury were undertaken in rats in view of the presence of a carbonyl function as well as hydroxyl groups in its chemical structure. In spite of its potentials to generate hydroxyl radicals, it is deemed to possess antioxidant property by virtue of its electrophilic nature. Recent studies have shown gastro-protection to mediate through a reaction between the electrophilic compounds and sulfhydryl groups of the mucosa. Hence it was found worthwhile to evaluate the interaction between the oxidant and antioxidant functions in the structure of the same compound. The effects of ninhydrin pretreatment on gastric mucosal injuries caused by 80% ethanol, 25% NaCl and 0.2M NaOH were investigated in rats. The gastric tissue in ethanol-treated rats was analyzed for different histopathological lesions. In addition, the effects on ethanol-induced changes in the gastric levels of proteins, nucleic acids, non-protein sulfhydryl (NP-SH) and malondialdehyde (MDA) were also evaluated. Ninhydrin, as such, failed to induce any significant changes in normal gastric mucosa, while its pretreatment at oral doses of 5, 10 and 20 mg/kg was found to provide a dose-dependent protection against the ulcers induced by ethanol, NaOH and NaCl. The results of histopathological evaluation revealed a protective effect of ninhydrin on congestion, hemorrhage, edema, erosions and necrosis caused by ethanol. Furthermore, the pretreatment afforded a dose-dependent inhibition of the ethanol-induced depletion of proteins, nucleic acids, NP-SH and increase of MDA in the gastric tissue. The results obtained clearly demonstrate the anti-ulcerogenic activity of ninhydrin. The exact mechanism of action is not known. However, the carbonyl function in ninhydrin appears to achieve antioxidant balance and protect the gastric mucosa from the ethanol-induced gastric injury. Further studies are warranted to investigate the toxicity and detailed mechanism of action of this potent compound before any clinical trials, especially at the effective lower doses.     

Behavioral and physiological characteristics of nonagouti mutation in gray rats during selection for aggressiveness

The goal of this work was to find out to which degree the black coat color mutation nonagouti that appears in wild Norway rat in the course of breeding for the maintenance and enhancement of aggressiveness towards a human affects selected and other behavioral traits as well as stress reactivity and brain neurochemistry. Nonagouti rats displayed increased emotionality in the open-field and forced-swimming tests as compared to agouti animals, whereas there were no differences in anxiety estimated in the elevated plus-maze. Neither were there any differences in glucocorticoid reactions to a combined stressful procedure such as forced swimming. The dopamine content in the frontal cortex and striatum and noradrenaline content in the frontal cortex were increased in black rats as compared to gray rats. The result suggest that the nonagouti mutation in gray aggressive rats enhances the effects of selection for aggressiveness on some behavioral traits and brain catecholamine level.     

Behavioral and biochemical effects of job loss and unemployment stress

Previous research on the effects of unemployment has focused upon both anticipation of job loss and long-term unemployment, typically using self-report and some biochemical measures of response to unemployment stress. The present study was concerned with behavioral and biochemical responses to unemployment. It was also designed to examine a somewhat different time course of unemployment than has been used in previous work. Results indicated that stress accompanies unemployment; looking at people who had been unemployed for up to four months, those who had been unemployed for greater lengths of time performed more poorly on a behavioral task and exhibited higher levels of urinary norepinephrine and epinephrine than did persons unemployed for shorter time periods or subjects who were employed.     

Gastric protective effect of peripheral PYY through PYY preferring receptors in anesthetized rats

The influence of intravenous peptide YY (PYY) on the gastric injury induced by 45% ethanol was investigated in urethane-anesthetized rats. PYY (25, 75, 125, and 250 pmol x kg(-1) x h(-1)) significantly reduced gastric lesions by 36, 59, 40, and 38%, respectively. Antibody against ratPYY (2 mg/rat) injected intravenously completely prevented the gastroprotective effect of intravenous PYY (75 pmol x kg(-1) x h(-1)), whereas injected intracisternally (460 microg/20 microl), it significantly prevented intracisternal PYY (24 pmol/rat)-induced 58% reduction of ethanol lesions but not that induced by intravenous PYY. Vagotomy did not influence the gastroprotective effect of intravenous PYY. The Y(1)/"PYY-preferring" receptor agonist [Pro(34)]PYY (75 pmol x kg(-1) x h(-1) iv) significantly decreased ethanol-induced gastric lesions by 82%, whereas [Leu(31), Pro(34)]NPY, a Y(1)/Y(3) agonist, and PYY-(3-36), a Y(2) agonist, had no effect. These data indicate that PYY-infused intravenously at doses reported to mimic postprandial peak blood levels prevents ethanol-induced gastric injury through vagal independent pathways and PYY-preferring receptors.     

LHRH and LH in peripubertal female rats following prenatal and/or postnatal ethanol exposure

The effects of pre- and postnatal exposure to ethanol (ETOH) on LHRH and LH were investigated. Pregnant and/or lactating dams were fed ETOH during: 1) gestation, 2) lactation, or 3) gestation-lactation. Female offspring were decapitated at 30 or 40 days-of-age; trunk blood was collected for plasma LH RIA; and hypothalamic tissues were collected for LHRH RIA. Hypothalamic LHRH content of all ETOH-exposed groups was less than that of non-ETOH-fed controls at 30 and 40 days-of-age (p less than 0.05). Plasma LH concentrations of all ETOH-exposed groups were less than those of non-ETOH-fed controls at 30 and 40 days-of-age (p less than 0.05). Also, at 30 and 40 days-of-age, the plasma LH concentrations of the animals exposed to ETOH during lactation and gestation-lactation were less than those of the animals exposed to ETOH during gestation (p less than 0.05). These data suggest that ETOH exposure during gestation and/or lactation negatively affects hypothalamic LHRH content of female rat offspring. Decreased hypothalamic LHRH content with corresponding lowered plasma LH concentration suggests that ETOH influences development or maturation of hypothalamic LHRH neurons by possibly decreasing their number or synthesizing capability.