Angeles Menendez-Patterson

Effects of low stress during pregnancy on certain parameters of the offspring

In recent years the effect of intense stress applied during pregnancy has been studied. In this work, we exposed the mother to low immobilization stress throughout the entire pregnancy. This treatment that increased the sexual capacity in males had no detectable effects on the reproductive behavior of females. A positive role of this phenomenon in nature is suggested, as the offspring of stressed mothers would be more capable of facing difficult and selective environments.

Stress and sexual behavior in male rats

Abstract The relationship between sexual behavior and stress in male rats was investigated. Stress induction by psychophysical immobilization fo 3 hours along three days caused significant alterations of the different parameters which make up the sexual behavior of male rats. An extension of the stressing situation from 3 to 6 hours under the same experimental conditions produced very similar sexual disturbances. Our experimental results suggest that effects of acute stress on sexuality may be independent of time.

Postnatal development of argyrophilic nucleolar organizer regions in the mammillary body of undernourished rats.

The effects of undernutrition during pregnancy and/or lactation periods on cortical structures have already been reported. However, its effect on non-cortical areas like the hypothalamic, that participates in the regulation of the autonomic nervous system or food intake, has not been extensively investigated. We studied the postnatal development of the medial mammillary nucleus (hypothalamus) in the rat offspring that had a dietary restriction in utero and during lactation. The argyrophilic nucleolar regions (Ag-NORs), that represent the transcriptional activity of the cell, were quantified in their neurons. No statistically significant differences were found in the results between the control and undernourished groups in the ages studied (7, 14, 21 and 30 days). However, a delay in the neuronal activity of the latter group was observed. A critical period in the development of this nucleus, at about 21 days of age, was also seen in both groups. After this age, the activity levels remained steady.

The development of oxidative metabolism in diencephalic structures of the rat : A quantitative study

A new method for quantitative determination of cytochrome oxidase (C.O.) activity was applied to diencephalic structures of the limbic system that are closely connected anatomically, that is, the mammillary bodies (MB) and the anterior nucleus of the thalamus (AT). This method makes it possible to easily evaluate the oxidative metabolic capacity of brain regions, an index of their functionality. By using this technique, we studied the postnatal development of both structures in Wistar rats of 14, 21, 30, and 120 days of age. Furthermore, animals of 730 days were included in order to evaluate the effects of aging on C.O. activity of these structures. The results showed a significant increase in the C.O. activity of the subdivisions of the AT, its levels remaining constant until the adult age, with a significant decrease in its activity in aged animals. In the MB, only the increase in C.O. activity of the medial mammillary nucleus (pars medialis) was significant until the adult age. A decrease of C.O. values with aging was significant only in the lateral mammillary nucleus. These data suggest that there is a wide heterogeneity in the maturation and aging of brain oxidative metabolism in diencephalic structures.

Effect of early pre- and postnatal acquired malnutrition on development and sexual behavior in the rat

In this paper we attempt to elucidate the effects on the rat offspring of undernourishment during pregnancy and lactation on the following parameters were examined: weight at birth and its evolution over a three-month period, sexual behavior of adult males, vaginal opening and sexual cycle of females, blood sugar, blood proteins, hematocrit, natremia, potassemia, body weight and weight of testicles, seminal vesicles and adrenal glands in males 5 months of age. Our results indicate highly significant decreases in body weight in experimental animals over a period of three months. Vaginal opening in experimental females is significantly delayed and their estrous cycle is shortened. Male sexual behavior shows decreases in neuromotor activity and prolongation of the refractory period in experimental male animals. Of the parameters monitored at 5 months of age, only blood sugar levels were significant decreased in experimental male rats. In view of these results, it can be concluded that in utero and lactation period malnutrition affects fundamental parameters of both development and reproductive function in the offspring.

Effects of ovariectomy on the oxidative metabolism of the central nervous system and adrenal glands in female hamster (Mesocricetus auratus).

We have studied the influence of ovariectomy on the oxidative activity of hypophysis, hypothalamus, posterior cortex, septal area, amygdala and adrenal glands, in female hamsters, because their neuroendocrine behavior seems to differ from that of rats. Our results show a decreasing the O2 uptake in the hypothalamus and adrenal glands and an increase in the rest of the structures.

Oxidative activity during the sexual cycle of the central nervous system, adrenal glands and ovaries in the hamster (Mesocricetus auratus).

The results indicate significant increases of the oxidative metabolism in the oestrus of the ovaries, hypothalamus and the posterior cortex, while in the amygdala this increase occurs in the phase of diestrus.

Influence of malnutrition during gestation and suckling on reproductive function and sexual behavior in rats

Abstract The effects of undernourishment during gestation and suckling on reproductive function and sexual behavior in female rats were explored. We measured the following: puberty judged by vaginal opening and first estrous, estrous cycle, and sexual behavior of adult females. Compared to controls, puberty in undernourished females was significantly delayed, but the estrous cycle and pregnancies did not show alterations. Female sexual receptivity, lordosis and lordosis quotient increased in malnourished animals. Thus, malnutrition in utero and during suckling affects fundamental parameters of both puberty function and sexual behavior in female rats. There were marked intersexual differences.

Sexual behavior of the pancreatectomized (95%) male hamster (Mesocricetus auratus)

Abstract The sexual behavior of the male hamster subjected to partial pancreatectomy (95%) has been studied during a period of 13 months. Measures of sexual behavior (latency of mounting, mounting, intromissions, latency intromissions-ejaculation and approximation) indicate that the pancreatectomized male hamster presents grave anomalies in the performance of its sexual behavior. The sexual pathology of these animals that occurs after a relatively short period of time following surgery appears in an abrupt from before the first hyperglycemic peak and is maintained throughout the development of experimental diabetes, independent of the duration of observation.

Undernutrition and Postnatal Development of Brain Oxidative Metabolism in Limbic Structures: A Quantitative Study.

The effects of food restriction during gestation, lactation and post-weaning were studied in rat brain structures (14,21 and 30 days). Oxidative metabolism was quantified in neurons from the anterior thalamus and mammillary bodies using a quantitative histochemical method for cytochrome c oxidase (CO). In all the rat brains studied, a significant increase in activity occurred in the control group from 14 to 21 days after birth which then remained constant up to 30 days. A similar pattern was observed in the undernourished group, although in the anterodorsal and anteromedial thalamic nuclei the rise in CO only occurred between day 14 and 30 and there were no significant age-related changes in the lateral mammillary nucleus. Undernutrition produced a significant drop in CO activity after 21 days in all the nuclei except the lateral mammillary nucleus. In the latter nucleus and also in the pars medialis of the medial mammillary nucleus this parameter decreased at 30 days. Our results suggest that undernutrition and nutritional rehabilitation have different effects on the diencephalic regions studied, which depends on age and region.