Lactational ethanol exposure: brain enzymes and [3H]spiroperidol binding

Assessment of Ethanol Exposure from Hand Sanitizer Use and Potential for Developmental Toxicity in Nursing Infants

Ingestion of ethanol during pregnancy is known to have detrimental effects on the fetus. Although the potential developmental effects of maternal ethanol intake during lactation are less well characterized, public health guidelines recommend avoidance of alcohol or, if alcohol is consumed, to allow for 1–2 h to pass before nursing. A proposal to classify ethanol as potentially harmful to breast‐fed children warrants an investigation of the potential adverse neurodevelopmental effects of low‐dose ethanol exposure during lactation. There currently are no studies that have examined neurodevelopmental outcomes from lactational exposure to ethanol from the use of topical products that contain ethanol, such as alcohol‐based hand sanitizers (ABHS). Furthermore, the epidemiological literature of lactational ethanol exposures from maternal alcohol consumption is limited in design, provides equivocal evidence of neurological effects in infants, and is insufficient to characterize a dose–response relationship for developmental effects. Toxicological studies that observed neurodevelopmental effects in pups from ethanol via lactation did so at exceedingly high doses that also caused maternal toxicity. In this investigation, blood ethanol concentrations (BECs) of breastfeeding women following typical‐to‐intense ABHS use were computationally predicted and compared to health benchmarks to quantify the risk for developmental outcomes. Margins of 2.2 to 1000 exist between BECs associated with ABHS use compared to BECs associated with neurotoxicity adverse effect levels in the toxicology literature or oral ethanol intake per public health guidelines. Neurodevelopmental effects are not likely to occur in infants due to ABHS use by breastfeeding women, even when ABHSs are used at intense frequencies.

Adverse neurodevelopmental effects of ethanol exposure are supported by toxicological studies; ethanol as a potential “lactation hazard” needs evaluation. A lactation hazard may not be applicable for all ethanol‐containing products, such as hand sanitizers. Furthermore, internal dose assessments of hand sanitizer use are lacking. Computationally modeled blood ethanol concentrations following hand sanitizer use are lower than concentrations associated with toxicological and guideline benchmarks. Therefore, there is low potential for the use of ethanol‐containing hand sanitizers to be a lactation hazard.

National Institute on Alcohol Abuse and Alcoholism Report on Moderate Drinking

In support of the 2005 update of the U.S. Department of Agriculture/U.S. Department of Health and Human Services Dietary Guidelines, the National Institute on Alcohol Abuse and Alcoholism was asked to assess the strength of the evidence related to health risks and potential benefits of moderate alcohol consumption, with particular focus on the areas of cardiovascular disease, breast cancer, obesity, birth defects, breastfeeding, and aging. The findings were reviewed by external researchers with extensive research backgrounds on the consequences and benefits of alcohol consumption. This report now serves as the National Institutes of Health's formal position paper on the health risks and potential benefits of moderate alcohol use.

Oxidative damage following chronic aluminium exposure in adult and pup rat brains

Aluminium is known to cause neurotoxic effects. In the past few years there has been an upsurge of interest in aluminium exposure through diet and environment, which might impair the development of mammals. The present in vivo study was designed to investigate the potential of aluminium to participate in either antioxidant or pro-oxidant processes in both developed and developing rat brain. Markers of oxidative stress were determined in rat brains exposed to AlCl3 (100 mg/kg body weight) for 8 weeks. The aluminium dose was given to adult rats for 8 weeks and in another group, exposure of aluminium for 60 days was done postnatally, 21 days to the feeding mother (lactation period) and 39 days to the rat pups. The results showed a statistically significant (p<or=0.01) increase in lipid peroxidation (LPx) as measured by production of malondialdehyde in both cerebrum and cerebellum of pup brains. A significant increase (p<or=0.001) in LPx was also observed in the adult group. Furthermore, aluminium exposure resulted in a significant decrease in superoxide dismutase and catalase activity in both regions of the brain of developing and developed rat brain. Thus the results of the present study suggest that in rats, aluminium (100 mg/kg body weight) has a pro-oxidant effect and thus acts as a neurotoxin.

Fetal alcohol exposure and adult tumorigenesis

Adult rats exposed to prenatal alcohol were evaluated for their susceptibility to either hormone- or chemical-inducing tumors. In the first study, rats exposed to prenatal alcohol displayed an increased propensity to beta-estradiol (E2)-induced adenohypophyseal prolactinoma. The susceptibility was manifest as a potentiated increase in anterior pituitary weight as well as in serum prolactin levels after 1 and 3 weeks but not 5 weeks of hormone treatment. Two weeks after withdrawing the E2-implant, the prolactinoma underwent involution and serum prolactin reversed to baseline levels. The high concentrations of serum corticosterone were also reduced but did not return to baseline levels after E2 removal. In the second study, nitrosomethylbenzylamine (NMBA) was utilized to induce esophageal cancer in adult rats. There were no significant differences in tumor incidence or size between the prenatal alcohol-exposed and the pair-fed cohorts. However, the NMBA-treated prenatal alcohol-exposed rats displayed a marked decrease in thymus: body wt ratio as well as adrenal gland hyperplasia. The results suggest that no single mechanism can account for the variable susceptibility displayed by the prenatal alcohol-exposed rats to chemical carcinogens. Some of the observed changes, however, may be attributable to the long-lasting adverse effects of prenatal alcohol exposure on the well-being of the adult host.

Effects of acute barbiturate administration, tolerance and dependence on brain GABA system: comparison to alcohol and benzodiazepines

Central nervous system depressants, e.g., barbiturates, alcohol and benzodiazepines, have a wide spectrum of activity in humans and animals. Evidence accumulated suggests that some of the pharmacological actions exerted by these agents may be mediated through GABA system by mimicking GABAergic transmission. This review attempts to summarize the evidence available as to how the GABA system plays a part in the barbiturate actions and the development of tolerance to and physical dependence on barbiturates. The comparisons of the effects of alcohol, barbiturates and benzodiazepines at different steps of GABA synapse are also presented. Furthermore, the results which have been reported in the literature are inconsistent. This may be due to differences in: (a) animal models used; (b) brain regions used; (c) protocols (dose, duration, form and route of administration, etc.) used in treating animals and/or (d) techniques (pharmacological, biochemical, physiological, etc.) used.

Prenatal ethanol exposure impairs lesion-induced plasticity in a dopaminergic synapse after maturity

This study examined the consequences of alcohol (ethanol) exposure during fetal life on lesion-induced dopaminergic synapse responsiveness (plasticity) in the olfactory tubercle of the adult rat. Normally, in the olfactory tubercle, olfactory bulbectomy elicits alterations in pre- and postsynaptic dopaminergic markers, including, respectively, (1) increased tyrosine hydroxylase activity and immunoreactivity, which is associated with dopaminergic axon sprouting, and (2) increased dopaminergic receptor density and potentiated dopamine activation of adenylate cyclase. We have utilized biochemical and quantitative immunocytochemical methodology to examine these synaptic markers in olfactory bulbectomized or sham-operated adult rats. These animals were offspring of dams which were administered one of the following diets during pregnancy: (1) liquid diet containing 35% ethanol-derived calories ad libitum; (2) liquid diet containing an isocaloric amount of maltose-dextrin instead of ethanol, pair-fed; or (3) unaltered liquid diet ad libitum. The results show that prenatal alcohol exposure leads to suppression of the lesion-elicited dopaminergic synapse responsiveness in the olfactory tubercle. There were no significant differences between offspring born to control and pair-fed animals, indicating that the observed abnormalities were not due to alterations in their nutritional status. In conclusion, the present data are a biochemical and quantitative immunocytochemical demonstration of impaired lesion-induced synaptic responsiveness. This renders a new dimension in support of previous evidence indicating that prenatal alcohol exposure leads to altered neuroanatomical, neuroendocrinological and behavioral responsiveness to various challenges. Such impaired synaptic responsiveness may underlie brain functional abnormalities characteristic of fetal alcohol syndrome.