THE EFFECT OF ETHANOL ON HABITUATION AND THE CARDIOVASCULAR-RESPONSE TO STIMULATION IN FETAL SHEEP

Fetal cardiovascular (CVS) changes, forelimb movements (FM) and rates of habituation to repeated stimulation, with suffusions of cold saline over the skin, were measured in 12 chronically catheterized fetal sheep aged 130-145 days. Stimulation of the fetuses caused a significant rise in heart rate (HR) (p < 0.01) and blood pressure (BP) (p < 0.001) and FM (p < 0.01). When the ewe was given an intravenous (i.v.) infusion of ethanol which produced fetal ethanol levels of 87 ± 1.1 mg/100 ml, the number of spontaneous FM decreased (p < 0.05). After i.v. ethanol, repeated stimulation of the fetuses still caused an increase in FM (p < 0.01) and a rise in HR (p < 0.05) and BP (p < 0.02) but the fetuses habituated more rapidly (7.25 ± 1.28 stimuli) compared to control experiments performed prior to (21.5 ± 3.57 stimuli) or after the ethanol (17.75 ± 5.83, p < 0.01). Fetal exposure to low concentrations of ethanol does affect the patterns of response and habituation of the developing fetal central nervous system. © 1990.