Administration of Low Doses of MK‐801 During Ethanol Withdrawal in the Developing Rat Pup Attenuates Alcohol's Teratogenic Effects

Abstract

Background Alcohol exposure during development can produce severe and long‐lasting central nervous system damage and consequent behavioral alterations. Recent evidence suggests that NMDA receptor‐mediated excitotoxicity during periods of withdrawal may contribute to this damage. We have demonstrated that blocking the NMDA receptor with MK‐801 during alcohol withdrawal can attenuate ethanol's adverse effects on behavioral development in the rat. This study examined the dose dependency of MK‐801's ability to mitigate ethanol's teratogenic effects.Methods Neonatal rat pups were exposed to 6.0 g/kg of ethanol in a binge‐like manner on postnatal day (PD) 6, a period of brain development equivalent to a portion of the human third trimester. Alcohol administration was accomplished with an artificial rearing procedure. Twenty‐one hours after ethanol treatment, pups were injected intraperitoneally with one of four doses of MK‐801 (0.05, 0.1, 0.5, or 1.0 mg/kg) or saline vehicle. An artificially reared control and a normally reared control group were included. On PD 18–19, activity level was monitored, and on PD 40–42, serial spatial discrimination reversal learning was assessed.Results Alcohol exposure on PD 6 produced significant increases in activity level and deficits in reversal learning. These alcohol‐induced behavioral alterations were significantly attenuated in subjects treated with one of the three lower doses (0.05–0.5 mg/kg) of MK‐801 during withdrawal. The performance of ethanol‐exposed subjects treated with the high dose of MK‐801 (1.0 mg/kg) did not differ from that of the Ethanol Only group.Conclusions These data suggest that alterations in NMDA receptor activation during alcohol withdrawal contribute to the neuropathology and consequent behavioral alterations associated with developmental alcohol exposure. These data have important implications for pregnant women and newborns undergoing ethanol withdrawal.