Down-regulation of 3H-imipramine binding sites in rat cerebral cortex after prenatal exposure to antidepressants

Several antidepressant drugs were given to pregnant rats in the last 15 days of gestation and 3H-imipramine binding (3H-IMI) was subsequently measured in the cerebral cortex of the offspring. The selective serotonin (5-HT) uptake blockers chlorimipramine and fluoxetine as well as the selective monoamine oxidase (MAO) inhibitors clorgyline and deprenyl induced, after prenatal exposure, a down-regulation of 3H-IMI binding sites at postnatal day 25. The density of these binding sites was still reduced at postnatal day 90 in rats exposed in utero to the MAO inhibitors. The antidepressants desipramine and nomifensine were ineffective in this respect. After chronic treatment of adult animals, only chlorimipramine was able to down-regulate the 3H-IMI binding sites. Consequently, prenatal exposure of rats to different antidepressant drugs affecting predominantly the 5-HT systems induces more marked and long-lasting effects on cortical 3H-IMI binding sites. The results suggest that the developing brain is more susceptible to the actions of antidepressants.     

Morphofunctional characteristics of the skin of newborn rat pups with prenatal exposure to desoxycorticosterone acetate

Desoxycorticosterone acetate (DOCA) was injected intramuscularly to pregnant rats at the III, or II-III trimester of pregnancy. By the end of pregnancy with increasing body mass of the female rats, the hormonal dosage dropped. The newborn rat skin was studied. The prenatal effect of DOCA resulted in thinning the epidermis, the decreasing dosage in certain activation of the epithelial proliferative activity and in appearance of foci of its hyperplasia. The hormone in the dose 0.8-1.0 mcg/100 g of the body mass activates the proliferative ability of fibroblasts, elevates the quantity of tissue basophils, increases secretory activity of both of them; this produces thickening of the derm. In the microvessels morphofunctional activity of endothelium increases, in the basal membrane contents of PAS-positive substances drop, the wall is often infiltrated with lymphocytes. Correlations between the cells and other structural components of the skin intensify. When the dose of DOCA increases and the time of the injection is short, the proliferative and secretory activity of fibroblasts is inhibited, but morphofunctional properties of the tissue basophils are stimulated. Congestive phenomena develop in the microvessels, mitotic activity of endotheliocytes is inhibited, in the basal membrane amount of the PAS-positive substances sharply decreases, perivascular edema develops in the connective tissue. Weakening or imbalance of the correlations is observed.     

The respiratory activity of the liver mitochondria and the viability of rat pups subjected to changes in their carbohydrate metabolism in the prenatal development period]

It is shown that hyperglycemia after insulin introduction to the pregnant rats delays oxidation of pyruvate and malate by liver mitochondria as well as decreases offspring vitality. Digestive hyperglycemia activates utilization of this intermediate by liver mitochondria, that increases the rat vitality.     

Effect of prenatal and postnatal cocaine exposure on somatostatin content and binding in frontoparietal cortex and hippocampus of developing rat pups.

The effects of cocaine administration to pregnant and/or nursing rats on somatostatin (SS) concentration and receptors in offspring brains at birth and 15 days of age were studied. SS was measured by radioimmunoassay and SS receptors by radio receptor assay in frontoparietal cortex and hippocampus. In newborn and 15-day-old animals the exposure to cocaine produced an increase in SS concentration in the frontoparietal cortex and a decrease of this parameter in the hippocampus. Administration of cocaine only during lactation did not induce such changes. Exposure during pregnancy or nursing induced in 0- or 15-day-old offspring an increase in the total number of SS receptors and a decrease in the affinity constant only in the cortex.     

Effects of prenatal cocaine exposure in the prefrontal cortex of the rat

This work was undertaken in order to assess the organization of the prelimbic area of the medial prefrontal cortex of rats exposed prenatally to cocaine. Pregnant Wistar rats were assigned to the following groups:

1. Cocaine—60 mg/kg body wt/d sc, from gestational days 8–22; 0131
2. Saline;
3. Pair-fed; and
4. Nonmanipulated.

Male offspring were perfused on postnatal days 14 and 30. Six brains per group and per age were embedded in celloidin to calculate the volumes of the prelimbic area; sections from the other six brains were embedded in resin and processed for electron microscopy. Using semithin sections (2 μm) of layers II–III and V–VI, the following parameters were calculated:

1. The fraction of the neuropil occupied by neurons (V_V);
2. The packing (N_A) density; and
3. The numerical (N_V) density.

Qualitative alterations consisted of dispersed profiles of degenerated neurons and dendrites in the medial prefrontal cortex. No significant differences were found in the gross morphometric parameters when the cocaine group was compared with the other groups. A high interanimal variation was shown in the prelimbic volumes of postnatal day (PND) 14 cocaine-treated rats, and a decrease in volumes was detected at PND30. Although there are some alterations in the main afferent cortical target area for dopaminergic input, its gross morphometric parameters do not seem to be sufficiently affected to account for the behavioral alterations referred to as being dependent on this brain region.     

Local exposure of the rat cortex to radiofrequency electromagnetic fields increases local cerebral blood flow along with temperature

Few studies have shown that local exposure to radiofrequency electromagnetic fields (RF) induces intensity-dependent physiological changes, especially in the brain. The aim of the present study was to detect reproducible responses to local RF exposure in the parietal cortex of anesthetized rats and to determine their dependence on RF intensity. The target cortex tissue was locally exposed to 2-GHz RF using a figure-eight loop antenna within a range of averaged specific absorption rates (10.5, 40.3, 130, and 263 W/kg averaged over 4.04 mg) in the target area. Local cerebral blood flow (CBF) and temperatures in three regions (target area, rectum, and calf hypodermis) were measured using optical fiber blood flow meters and thermometers during RF exposure. All parameters except for the calf hypodermis temperature increased significantly in exposed animals compared with sham-exposed ones during 18-min exposures. Dependence of parameter values on exposure intensity was analyzed using linear regression models. The elevation of local CBF was correlated with temperature rise in both target and rectum at the end of RF exposure. However, the local CBF elevation seemed to be elevated by the rise in target temperature, but not by that of the rectal temperature, in the early part of RF exposure or at low-intensity RF exposure. These findings suggest that local RF exposure of the rat cortex drives a regulation of CBF accompanied by a local temperature rise, and our findings may be helpful for discussing physiological changes in the local cortex region, which is locally exposed to RF.     

Influence of core temperature on autoresuscitation during repeated exposure to hypoxia in normal rat pups.

Failure to autoresuscitate by hypoxic gasping during prolonged sleep apnea has been suggested to play a role in sudden infant death. Furthermore, thermal stress brought about by a contribution of infection, overwrapping, or excessive environmental heating has been shown to be associated with an increased risk of sudden infant death, particularly in prone sleeping infants. The present experiments were carried out on newborn rat pups to investigate the influence of "forced" changes in core temperature on their time to last gasp during a single hypoxic exposure and on their ability to autoresuscitate during repeated exposure to hypoxia. On day 5 or 6 postpartum the pups were placed in a temperature-controlled chamber regulated to 33, 35, 37, 39, or 41 degrees C and exposed to a single period of hypoxia (97% N(2)-3% CO(2)) and their time to last gasp was determined, or they were exposed repeatedly to hypoxia and their ability to autoresuscitate from primary apnea was determined. Increases in core temperature brought about by changes in ambient temperature from 33 to 41 degrees C decreased the time to last gasp after a single hypoxic exposure and decreased the number of successful autoresuscitations after repeated hypoxic exposures. Thus our data support the hypothesis that forced changes in core temperature brought about by changes in ambient temperature influence protective responses in newborns that may prevent death during hypoxia, as may occur during single or repeated episodes of prolonged sleep apnea.     

The effect of DMCM and diazepam on the behavior of rats subjected to ethanol exposure in the prenatal period]

White rats were given 4 g/lag daily of 40% ethyl alcohol from the 5th till the 20th day of pregnancy. Males of the off-spring from the 5th till 19th day were subjected to treatment with 0.6 mg/kg DMCM (4-ethyl-6, 7-dimethoxy-beta-carboline-3-carboxylate methyl ether) or 2.5 mg/kg of diazepam daily. It has been shown that both drugs normalize increased locomotor activity; treatment with DMCM corrects passive avoidance conditioned reflex retention; both drugs restore active avoidance conditioned reflex elaboration in rats alcoholized prenatally. Moreover, treatment with DMCM or diazepam restores correlations between behaviour indices and binding of 3H-diazepam which have been altered by prenatal alcoholization.     

Ultrastructure of the serotoninergic system of the motor area of the cerebral cortex

Owing to the microscopical investigation, using selective neurotoxin 5,7-dihydroxytryptamine, it has been possible to reveal the serotoninergic system and targets of its innervation in the rat cerebral cortex motor area. The serotoninergic axonal varicosities and synaptic boutons are present in all layers of the neocortex. Their large amount is revealed in the I and II layers. The terminals form contacts with dendrites of small size, sometimes they terminate on the head of the spines, as well as on bodies of neurons in different layers. According to their position and ultrastructural organization these neurons are, perhaps, pyramidal, that is glutamatergic, and those less in their size--refer to interneurons and can be GABAergic ones. Basing on own data and those of the literature, concerning the existence of nonsynaptic link for transmission of serotoninergic effects, a conclusion is made that a coordinating functioning of the synaptic and non-synaptic intercellular integrative mechanisms ensure a wide range of functions of the serotoninergic system in the cerebral cortex.     

Alpha fetoprotein in maternal blood during normal and pathological pregnancies]

AFP was assayed in serum of normal pregnant women and in patients with pathological pregnancy. Pathological levels of AFP, defined as increased or decreased concentrations compared with the normal distribution, was detected in 83.5 % of pregnant women who delivered a dysmature child and in 88 % of those whose placenta was macroscopically sclerous. A longitudinal determination of AFP appears to be useful in the follow-up of risk of abortion.