Maternal ethanol consumption: Binding of l-glutamate to synaptic membranes from whole brain, cortices, and cerebella of offspring

Abstract

We examined the influence of chronic maternal ethanol consumption on the Na +- and Ca 2+-independent binding of l-glutamate to synaptic plasma membranes from whole brain as well as from cortices and cerebella of developing offspring. The maximum specific binding ( B max) of l-glutamate to the Na +- and Ca 2+-independent binding sites in synaptic plasma membranes of brain peaked at 17 days of age in the offspring of both control and ethanol-fed rats, although at that age there were significantly fewer binding sites in the brains of the offspring of ethanol-fed rats. The regional localization of this deficit is not now known. However, it appears that one major glutamatergic region (the cortex) does not reflect the transient deficiency of l-glutamate sites in brain. In fact, the concentration of l-glutamate binding sites in cortical synaptic plasma membranes was significantly increased in the 20-day-old offspring of ethanol-fed rats. In contrast to the cortex, binding to cerebellar synaptic plasma membranes was comparable in 20-day-old offspring of control and ethanol-fed rats. Despite transient alterations in the concentrations of l-glutamate binding sites in brain and synaptic plasma membranes, the affinity of the sites for l-glutamate ( K d) was consistently normal in the 14- to 26-day-old offspring of ethanol-fed rats.