Increased synaptic contacts of catecholaminergic boutons in the cerebral cortex and paraventricular hypothalamic nucleus of rats after prenatal and perinatal ethanol exposure

Alcohol exposure during development alters hypothalamic neurotransmitter concentrations

The effect of exposure to alcohol during a period roughly equivalent to the human third trimester on neurotransmitter content in the rat hypothalamus was examined. The alcohol exposure was accomplished via an artificial rearing procedure. The alcohol group was exposed to 5 g/kg/day of ethanol from postnatal day (PD) 4 to 10. There was an artificially reared control group not exposed to alcohol and a normally reared control group. Noradrenaline, dopamine, homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin, and 5-hydroxyindoleacetic acid (5-HIAA) concentrations were measured using high performance liquid chromatography with electrochemical detection in juvenile and adult rats. There were no effects in juvenile rats. In adult rats, alcohol exposure from PD 4 to 10 increased hypothalamic content of noradrenaline, dopamine, serotonin and 5-HIAA. While adult females had greater amounts of hypothalamic serotonin and 5-HIAA than adult males, there were no interactions of sex with alcohol exposure. These results suggest that hypothalamic function is seriously disrupted by alcohol exposure during development.

Ethanol alters monoamines in specific mouse brain regions

Ethanol (3.5 g/kg 60 min post-IP injection) produced the following changes in regional brain monoamine levels and in the respective metabolite/neurotransmitter ratios: for the noradrenergic system, MHPG was decreased in the amygdala and increased in the hypothalamus, while the MHPG/NE ratio was increased in the prefrontal cortex and the hypothalamus. For the dopaminergic system, DA was decreased in the olfactory tubercle, DOPAC was increased in the prefrontal cortex and septum, and DOPAC/DA was increased in the prefrontal cortex, septum, striatum, and hypothalamus. HVA was increased in the prefrontal cortex and septum, while HVA/DA was increased in the same regions plus the olfactory bulb. 3MT was decreased in the olfactory tubercle and striatum. The serotonergic system was not altered. The results demonstrate that ETOH produces selective regional changes in the concentration and utilization of monoamines in mouse brain with a predominant influence on dopaminergic systems and a lesser effect on noradrenergic activity.

The effects of maternal ethanol exposure on neurotransmission and second messenger systems: a quantitative autoradiographic study in the rat brain

The effects of maternal ethanol exposure on neurotransmission and second messenger systems were examined in rats using histochemistry and in vitro autoradiography. Thirty % ethanol was administered to pregnant rats from gestational day 7 to the day of delivery. Quantitative autoradiography was used to map muscarinic cholinergic, dopamine D2, adenosine A1, and inositol 1,4,5-trisphosphate binding sites, as well as to localize adenylate cyclase and protein kinase C. We found no difference in the patterns of staining with acetylcholinesterase and Timm's stain between control and prenatally ethanol-exposed rats on postnatal day (PN) 30. In the ethanol-exposed rats, [3H]forskolin binding sites were increased during early development in the CA1 subfield of the hippocampus and the occipital cortex; [3H]phorbol ester binding sites were increased in the cortex, striatum, and hippocampus; hippocampal muscarinic cholinergic sites were increased on PN4 and 30; adenosine A1 binding was reduced on PN10 in most regions examined, but was increased in the CA1 subfield on PN30; dopamine D2 receptor levels were significantly reduced on PN30 in the striatum; and IP3 receptors were decreased in most regions studied, but particularly in the cerebellum. Thus, some of these changes were transient and others were long-lasting. Although histopathological abnormalities were minimal, the alterations of binding sites in the cerebellum (the coordination center) and in the hippocampus (related to memory and learning) that were detected may contribute to the behavioral and mental deterioration seen in the fetal alcohol syndrome.