ROLE OF NORADRENERGIC INNERVATION OF BROWN ADIPOSE-TISSUE IN THERMOREGULATORY DEFICITS FOLLOWING PRENATAL ALCOHOL EXPOSURE

The development of thermoregulation in newborns is delayed by prenatal alcohol exposure in an animal model of moderate maternal drinking. Ne wborn mammals generate heat primarily via nonshivering thermogenesis i n brown adipose tissue (BAT), which is activated by the sympathetic ne rvous system. In this study, the effects of prenatal alcohol exposure on the development of the sympathetic innervation of BAT was investiga ted by assessing the concentration of norepinephrine (NE) in interscap ular BAT. Pregnant dams were given either a liquid diet with 35% of th e calories derived from alcohol, a liquid diet without alcohol to cont rol for any effects of the liquid diet administration, or ad libitum f ood and water. Interscapular brown adipose tissue was excised from 5-, 10-, and 20-day-old male and female offspring. At 5 days of age, alco hol-exposed pups had significantly lower NE concentrations than did pu ps in either control group. However, 20-day-old alcohol-exposed pups h ad significantly higher NE concentrations than either control group. T hese results suggest a delay in the development of the sympathetic act ivation of BAT thermogenesis, followed by a compensatory overactivatio n. These findings may have important implications for understanding th e mechanisms underlying thermoregulatory deficits seen after prenatal alcohol exposure. In addition, these results suggest that maternal alc ohol consumption may increase the risk of sudden infant death syndrome , which has been linked to inappropriate BAT thermogenesis.