Gestational Age-Dependent Interplay between Endocannabinoid Receptors and Alcohol in Fetal Cerebral Arteries

Alcohol (ethanol) is one of the most widely consumed drugs. Alcohol consumption by pregnant women may result in a range of fetal abnormalities termed fetal alcohol spectrum disorders (FASDs). The cerebrovascular system is emerging as a critical target of alcohol in the developing brain. We recently showed that three episodes of prenatal alcohol exposure resulting in 80 mg/dL alcohol in maternal blood during mid-pregnancy up-regulated anandamide-induced dilation of fetal cerebral arteries. Moreover, ethanol dilated fetal cerebral arteries via cannabinoid (CB) receptors. Whether a critical role of fetal cerebral artery CB system in responses to alcohol was maintained throughout the gestation, remains unknow.

Pregnant baboons (second trimester equivalent) were subjected to three episodes of either alcohol or control drink infusion via gavage. Cerebral arteries from mothers and near-term female fetuses were in vitro pressurized for diameter monitoring.

Near-term fetal and maternal arteries exhibited similar ability to develop myogenic tone, to constrict in presence of 60 mM KCl, and to respond to 10 µM anandamide. Fetal and maternal arteries largely failed to dilate in presence of 63 mM ethanol. No differences were detected between arteries from control and alcohol-exposed baboon donors. Therefore, previously observed ethanol-induced dilation of fetal cerebral arteries and up-regulation of CB components in response to fetal alcohol exposure during mid-pregnancy was transient and disappeared by near-term.