Neonatal behavioral toxicity in rats following prenatal exposure to methanol

Although methanol (MEOH) may assume a significant role as a fuel, which implies wide availability, little is known of its toxicity apart from acute poisoning episodes in human adults. Even less is known about its toxicity in developing organisms. This experiment studied the early behavioral development of rats whose mothers had consumed MEOH during gestation by measuring the responses of suckling (postnatal day 1) and nest-seeking (postnatal day 10). Primigravida Long-Evans rats were divided into three groups (N = 10). Two of the groups consumed drinking solutions of 2% MEOH instead of distilled water either on gestational days 15-17 (MEOH 1) or 17-19 (MEOH 2). No maternal toxicity was apparent as measured by weight gain, gestational duration, and daily fluid intake. Daily MEOH consumption averaged 2.5 gm/kg over the 3-day period in both MEOH groups. Litter size, birth weight, and infant mortality did not differ among the three groups. Postnatal growth and date of eye opening were unaffected. MEOH pups required longer than controls to begin suckling on postnatal day 1. On postnatal day 10, they required more time to locate nesting material from their home cages. These data suggest that prenatal MEOH exposure induces behavioral abnormalities early in life that are unaccompanied by overt toxicity.