Offspring Of Ethanol-treated Rats Research Articles

Prenatal exposure to ethanol causes differential effects in nerve growth factor and its receptor in the basal forebrain of preweaning and adult rats.

In this study we investigated nerve growth factor (NGF) levels in the cortex and hippocampus of the offspring of pregnant female Sprague-Dawley rats receiving a single intragastric administration of acute ethanol on the 15th day of gestation and compared them with a control group of rats that received an injection of sucrose. We also examined the distribution of the low-affinity NGF receptor, p75NGFR, on NGF-responsive neurons that are localized in the septum and the nucleus of Meynert, which receive the respective trophic support from the hippocampus and the cortex. In the ethanol-treated group, the results show that at post-natal age 15 days, the NGF septohippocampal pathways were markedly affected. At day 15, the NGF level was significantly higher in the offspring of ethanol-treated rats. By day 40, NGF values in both groups decreased to similar levels. At day 60, however, the NGF level in the ethanol-treated animals decreased to a significantly lower value than that of the control group, which remained essentially unchanged. In parallel, at day 60 the numbers of septal cholinergic neurons expressing p75NGFR were also significantly lower in ethanol-treated rats than in control animals. Because ethanol is known to induce neurological disorders, as well as deficits in cell proliferation and differentiation, the results suggest that one cause of the deleterious effects induced by ethanol is the low availability of NGF during certain stages of postnatal brain development.

Effects of prenatal ethanol exposure on dendritic spines of layer V pyramidal neurons in the somatosensory cortex of the rat

The number of dendritic spines on consecutive segments from the cell body along the 400–600 μm proximal region of the apical dendrites of layer V pyramidal neurons, impregnated with the rapid Golgi method, in the somatosensory cortex was counted in ethanol-treated rats during gestation (25% ethanol in drinking water representing 30–35% of the total caloric intake) and in age-matched controls at postnatal ages 4, 15, 30 and 90 days. Although the mean values were lower in ethanol-treated rats than in controls during the first fortnight of postnatal life, significantly lower numbers of spines were observed only in the 15-day-old rat (Student's t-test, P < 0.01−0.001). Spines with long, thin pedicles were characteristically encountered in ethanol-treated and controls aged 4 days; this sort of spine also predominated in ethanol-treated rats aged 15 days, but not in age-matched controls. The decrease in number and the abnormal morphology of spines was no longer present in ethanol-treated rats aged 30 and 90 days. These data suggest that impaired maturation of dendritic spines on cortical pyramidal cells, followed by recovery of the altered parameters at the end of the first postnatal month, occurs in the offspring of ethanol-treated rats during gestation.

Effects of prenatal ethanol exposure on physical growth, sensory reflex maturation and brain development in the rat.

In the offspring of ethanol-treated rats during gestation (25% ethanol in drinking water) decreased litter size, increased postnatal mortality rate, reduced body weight and body size, delayed ear opening, eyelid opening and teeth eruption, retarded air righting reflex acquisition, impaired brain growth, reduced cortical thickness and delayed maturation of layer Vth's pyramidal neurons: reduced basilar dendritic arborization and decreased number of spines in the apical dendrite, were observed when compared with age-matched controls fed with a standard diet. Minimal effects were found in the offspring of fibre-treated rats during gestation (standard diet mixed with cellulose) in which the body weight was similar to that of controls, although both the calorific intake from food and the mother's weight gain during pregnancy were similar to those of the ethanol-treated group. All these abnormal parameters became normal at the end of the first month of postnatal life, indicating recovery of these developmental defects produced by prenatal ethanol consumption.

Synaptic membrane phospholipids: Effects of maternal ethanol consumption

The cholesterol and phospholipid content and phospholipid composition were determined in synaptic membranes from the 17- to 31-day-old offspring of rats that were pair-fed either a control or 6.6% ( v v ) ethanol liquid diet on a chronic basis prior to parturition. At all ages examined, the major synaptic membrane phospholipid was phosphatidyl choline (>40%). Other prominent synaptic membrane phospholipids included phosphatidyl ethanolamine (∼17 to 21%), ethanolamine plasmalogen (∼5 to 16%), and phosphatidyl serine (∼13%). Smaller proportions of sphingomylein (4 to 7%), phosphatidyl inositol (∼1%), and phosphatidic acid (∼1%) were detected. Between 17 and 31 days of age, there was a significant decrease in the proportion of phosphatidyl choline and a significant increase in the proportion of ethanolamine plasmalogen. When the offspring of control and ethanol-treated rats were compared, no significant differences were found in either the yield of synaptic membrane protein, or in the concentration of synaptic membrane cholesterol and total phospholipid. However, the proportion of ethanolamine plasmalogen was significantly decreased in the 24-day-old offspring of ethanol-treated rats, suggestive of a delay in the normal development-related increase of this lipid. In addition, there was a small increase in the proportion of sphingomyelin in the 31-day-old offspring of ethanol-treated rats.

Dopamine, serotonin, and acid metabolites in brain regions from the developing offspring of ethanol-treated rats.

Female rats were pair-fed control or ethanol liquid diets on a chronic basis prior to parturition. Six brain regions (hypothalamus, cerebellum, brain stem, cortex, corpus striatum, and hippocampus) were dissected from 19- and 35-day-old rat offspring for the determination of dopamine (DA), serotonin (5-HT), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA). DA, 5-HT, and the acid metabolites were separated simultaneously by reverse-phase HPLC and were quantitated using electrochemical detection. Between 19 and 35 days of age in control rats we observed an increase in the concentration of 5-HT and 5-HIAA in the corpus striatum and hippocampus and a decrease in these compounds in the cerebellum. In addition, there was a development-related decrease of 5-HIAA in the hypothalamus and an increase in the brain stem. During the same age period the concentration of dopamine increased in the hypothalamus and corpus striatum. There was also a development-related decrease in the concentration of DOPAC in the corpus striatum and an increase in the cortex as well as a decrease in HVA in the cerebellum and cortex. In comparison to age-matched control animals the 19- and 35-day-old offspring of ethanol-treated rats had a lower concentration of 5-HT and/or 5-HIAA in the cortex, cerebellum, and brainstem. In addition the 35-day-old offspring of ethanol-treated rats exhibited a decrease in DA and HVA in the cortex. The results of the present study suggest that in utero ethanol exposure affects both the serotonergic and dopaminergic systems in brain.

Brain myelination in the offspring of ethanol-treated rats: in Utero versus lactational exposure by crossfostering offspring of control, pairfed and ethanol treated dams

Pregnant Long-Evans rats were received on day 5 of gestation and divided into 4 treatment groups: (1) 27% calories provided as ethanol in a liquid diet; (2) pairfed i.e., isocaloric liquid diet restricted to match group (1); (3) liquid diet provided ad libitum; and (4) laboratory chow and water provided ad libitum. Litters were culled to 8 pups at birth and crossfostered across dams in all 4 groups to provide offspring falling into 16 different experimental groups, including some exposed to ethanol in utero only and some exposed only during lactation. At birth, blood alcohol levels of dams, culled pups and alcohol levels in the stomach contents of culled pups were measured. All pups were weaned and fed laboratory chow and water ad libitum from 21 days onward. At ages 16, 21, 30 and 52 days, pups were sacrified, and organ/body weight ratios and brain myelin concentrations were determined. Ethanol treated dams had longer gestational periods. The offspring of ethanol treated dams which were crossfostered to pairfed and well nourished dams during lactation had delayed eye opening, persistent lag in body growth and slightly lower brain myelin concentrations. Offspring of dams which were either pairfed or well nourished during gestation, but crossfostered during lactation to ethanol treated dams, had abnormal organ weights, abnormal brain weights and severely depressed brain myelin concentrations persisting through 52 days of age. Thus, lactational ethanol effects on brain myelin were more severe than gestational effects; body growth was affected more severely by gestational exposure, and gestational effects were generally less severe with adequate nutrition.

Maternal ethanol consumption and synaptic membrane glycoproteins in offspring.

The present study was undertaken to assess the influences of chronic maternal ethanol consumption, prior to and during gestation, on the development of synaptic plasma membranes (SPMs) and on the synthesis of SPM glycoproteins in offspring. Comparisons were made between animals whose mothers were pair-fed a control or 6.6% (v/v) ethanol liquid diet in which protein accounted for either 18% (original) (C & E) or 21% (revised) (*C & *E) of the calories. In addition, groups of pups that were either cross-fostered (*C & *E) with chow-fed surrogate mothers or reverse cross-fostered (offspring of chow-fed mothers with *C & *E mothers) were examined. Ethanol and matched (same dietary group) control pups had comparable brain and body weights, brain protein content, and yield of SPM proteins during the 10-24 day age period examined. However, the yield of SPM proteins from ethanol and control offspring of and/or reared by the three groups of rat mothers that received the *E and *C liquid diets was greater than that of the offspring of rats that were fed the original diets. This suggests that the original diets were not nutritionally adequate for pregnant rats. Despite the fact that the content of SPM proteins was comparable in ethanol and matched control pups, the offspring of ethanol-treated rats had an abnormal distribution of [3H]- or [14C]-fucose-derived radioactivity among SPM glycoproteins. The SPM abnormalities were most severe in the non-cross-fostered offspring of E rats. No SPM glycoprotein abnormalities were found in the reverse cross-fostered group. The results of the present study demonstrate that chronic maternal ethanol consumption prior to parturition has a severe effect on the synthesis of SPM glycoproteins in developing offspring without affecting the content of SPMs per se. It also demonstrates the importance of optimizing the composition of liquid diets used to feed pregnant rats.