Alterations In Adult Rats Research Articles

Long‐term behavioural and molecular alterations associated with maternal separation in rats

In this study we addressed whether certain behavioural measures, endocrine levels and specific stress-related proteins exhibit long-term alterations in adult rats following repeated postnatal maternal separation. Rats were subjected to daily maternal separation for 15 min (HMS15) or 180 min (HMS180) from postnatal day 2-14. Adult HMS180 animals were hypoactive and had increased levels of stereotypy compared to HMS15 and normal animal facility-reared (AFR) animals. HMS180 animals also had augmented plasma adrenocorticotropin (ACTH) and corticosterone (CORT) concentrations following an acute stressor, compared to the other two groups. We assessed persistent changes in proteins regulated by stress in hippocampus, cortex, ventral tegmental area, nucleus accumbens, striatum and amygdala. Western blotting analysis revealed a decrease in the levels of mature brain-derived neurotrophic factor (BDNF) in hippocampus and striatum, but an increase in the ventral tegmental area in the HMS180 rats. Levels of pro-BDNF were significantly increased in the ventral tegmental area of HMS180 animals but were unchanged in other brain regions compared to the other two groups. Levels of the transcription factors cAMP response element binding protein (CREB) and DeltaFosB were unchanged in all of the brain regions studied in the maternally separated rats. These data show that maternal separation induces long-term changes in BDNF expression, and more specifically the processing of BDNF, in the hippocampus, striatum and ventral tegmental area. Recognition of these adaptations begins to define the brain regions, and neural circuitry, associated with persistent alterations induced by early life stressors and the development of mood disorders.

Neonatal maternal deprivation promotes Nippostrongylus brasiliensis infection in adult rats

Neonatal stress is known to alter immune responses in adults and parasitic infection is modulated by the immune status of the host. The present study aimed to establish whether neonatal maternal deprivation affects the time course of Nippostrongylus brasiliensis infection and associated intestinal alterations in adult rats. Rat pups were separated from their dam 3 h daily during postnatal days 2–14, or left undisturbed. At 12 weeks of age, N. brasiliensis infection was induced by subcutaneous administration of 3000 L3 larvae. At 7 and 12 days after primary infection, the number of intestinal adult worms, fecal egg output, jejunal paracellular permeability, and myeloperoxidase (MPO) activity were measured. On days 7 and 12 after a secondary infection, numbers of adult worms and egg production were determined. Maternal deprivation increased the number of jejunal adult worms and fecal eggs and larvae on day 7 after primary infection, and exacerbated the increase in jejunal MPO activity induced by the infection. On day 12, adult worms were only observed in deprived rats. N. brasiliensis infection did not potentiate the increase in jejunal paracellular permeability induced by maternal deprivation. After the second infection, no egg was detected in both control and deprived rats. In conclusion, maternal deprivation in rats facilitates primary infection by N. brasiliensis and enhances the inflammatory response of the jejunum, but does not induce severe breakdown of immunity to N. brasiliensis.

Morphometric investigations of the mitochondrial damage in ceroid lipopigment accumulation due to vitamin E deficiency

Numeric (Nv) and volume (Vv) densities, as well as the average size (skeleton: Sk) of synaptic mitochondria from adult, normally fed and adult, vitamin E deficient animals (11 months of age) were semiautomatically measured by computer-assisted morphometry in the cerebellar granular layer. Nv, Vv and the average mitochondrial volume ( V) were measured on perikaryal Purkinje cell organelles preferentially stained for succinic dehydrogenase (SDH) activity. Adult vitamin E deficient animals showed a significant decrease of Nv, a significant increase of Sk and an unchanged value of Vv. While in adult normally fed animals the mitochondria of increased size (Sk>5 μm) were 5.3%, in the adult vitamin E deficient rats this fraction accounted for 25.5%. In Purkinje cell perikarya, vitamin E deficiency resulted in a significant decrease of Vv, Nv and V, as well as a steeper reduction of the percentage of SDH-positive mitochondria of larger size. Taken together, these findings document that vitamin E deficiency is responsible of mitochondrial morphometric alterations in adult rats. Structurally deteriorated mitochondria are reported to play a role in producing increased amounts of free radicals, which can facilitate the accumulation of ceroid pigment.

Prenatal stress induces long-term sleep alterations in adult rats: Implication for depression

Prenatal stress induces long-term sleep alterations in adult rats: Implication for depression

Neonatal desipramine treatment alters free-running circadian drinking rhythms in rats

Neonatal treatment with monoamine reuptake inhibitors results in a constellation of neurobehavioral alterations in adult rats that may model human depression. Since alterations in circadian rhythmicity have been reported in both depressed patients and in animal depression models, the present study examined the effects of neonatal desipramine treatment (5.0 mg/kg SC from postnatal day 7 through 22) on free-running circadian drinking rhythms. Rhythmicity was examined in constant darkness (DD), constant light (LL), and during adult desipramine treatment (0.25 mg/ml via the drinking water). Compared with saline-treated controls, neonatal desipramine lengthened free-running period in DD, blunted the period-altering effect of LL, and potentiated the period-altering effect of adult desipramine treatment. Neonatal desipramine treatment also increased circadian amplitude and spectral magnitude, but did not modify the effects of light or adult desipramine on these parameters. These results provide further evidence that behavioral depression is associated with alterations in circadian rhythmicity, and are consistent with the hypothesis that such relationships are mediated by brain monoaminergic systems.

Craniofacial Alterations in Adult Rats Prenatally Exposed to Ethanol

The rat was studied to determine whether gestational exposure to moderate amounts of ethanol produces permanent craniofacial malformations. Pregnant Long-Evans rats were fed a liquid diet containing 35% ethanol-derived calories or an isocaloric liquid diet between gestation days 6 and 20. Various dimensions of skulls and mandibles from adult male offspring were measured. All measurements taken in the parasagittal and coronal planes were significantly smaller in the ethanol-exposed rats than in the offspring of pair-fed controls. None of the vertical measurements was significantly altered. This report demonstrates that gestational exposure to ethanol in rats, at doses which produce lasting behavioral effects, also produces a specific constellation of craniofacial dysmorphisms without concomitant decreases in body weight.

Craniofacial alterations in adult rats prenatally exposed to ethanol

The rat was studied to determine whether gestational exposure to moderate amounts of ethanol produces permanent craniofacial malformations. Pregnant Long-Evans rats were fed a liquid diet containing 35% ethanol-derived calories or an isocaloric liquid diet between gestation days 6 and 20. Various dimensions of skulls and mandibles from adult male offspring were measured. All measurements taken in the parasagittal and coronal planes were significantly smaller in the ethanol-exposed rats than in the offspring of pair-fed controls. None of the vertical measurements was significantly altered. This report demonstrates that gestational exposure to ethanol in rats, at doses which produce lasting behavioral effects, also produces a specific constellation of craniofacial dysmorphisms without concomitant decreases in body weight.

Testicular torsion: temporal considerations

Unilateral testicular torsion may result in contralateral testicular alterations which appear immunologically mediated and avoidable by immunosuppression or orchiectomy of the twisted testicle within 24 hours. This study was instituted to assess three temporal aspects of these observations: (1) The effect of prepubertal torsion was studied. It was found that after prepubertal torsion, the contralateral testicle underwent normal development. (2) The duration of torsion necessary to result in contralateral testicular alterations in adult rats was studied. Deoxyribonucleic acid (DNA) histograms were utilized to assess disturbed spermatogenesis. After greater than 8 hours of torsion, detorsion offered no protection to the contralateral testicle. Marked alterations occurred in DNA histograms of 60% to 80% of the animals. (3) The duration and significance of these alterations were assessed. The alterations persisted in the contralateral testis 6 months, and the fertility rates were significantly lower than for control animals.

Early effects of feeding upon hormonal and metabolic alterations in adult rats with ventromedial (VMH) lesions.

The importance of the nutritional state for the development of metabolic alterations after ventromedial hypothalamic (VMH) destructions has been investigated. In the first experiment, groups of fed and 12 hours fasted animals were operated, given an intraperitoneal injection of 3H2O (1 mCi), and left without food until sacrificed 12 hours postoperatively. The lipogenesis in liver and adipose tissue, and the plasma levels of insulin, glucose, urea, free fatty acids (FFA) and triglycerides (TG) were measured. Animals operated in the fed state had increased lipogenesis in parametrial adipose tissue and hypoglycemia compared to their controls, whereas we found no differences between the groups which had been fasted 12 hours before surgery. In the second experiment, animals were deprived of food for 12 hours before being lesioned or sham-operated, and for 12 more hours postoperatively. They were then given one meal by stomach tube, and groups were killed 2, 4, 8 and 12 hours later. The following differences between groups were observed: 2 hours after feeding, the lesioned animals had increased plasma TG levels, but decreased liver lipogenesis. 4 hours after feeding, animals with lesions were hypoglycemic, and had lower plasma levels of FFA and TG than the controls. Hypoglycemia in lesioned animals was found also 8 hours after feeding, together with increased plasma TG levels. 12 hours after feeding, increased liver lipogenesis in lesioned animals was the only difference observed between the groups. The third and last experiment investigated the effect of three meals given 12, 18 and 24 hours postoperatively. Lesioned animals sacrificed 4 hours after the third meal had hypoglycemia, increased plasma TG levels, and increased lipogenesis, both in liver and adipose tissue. The metabolic differences between lesioned and sham-operated animals persisted also 8 hours after the last meal, except for the lipogenesis in adipose tissue. No differences in plasma insulin levels between animals with lesions or sham-operations were observed in these experiments.

Electrocardiographic Alterations in Adult Rats a Result of Acute Thiamine Deficiency

Electrocardiographic Alterations in Adult Rats a Result of Acute Thiamine Deficiency