Prenatal nicotine exposure: Effects on locomotor activity and central [I-125]alpha-BT binding in rats

Maternal smoking during pregnancy or in utero exposure of the fetus to nico tine may result in learning difficulties and hyperactivity in the child. To elucidate possible involvement of the alpha(7) nicotinic receptor subtype in these behavioral impairments. pregnant dams were treated with nicotine ( 9 mg/kg/day) via osmotic minipumps throughout gestation. Male offspring wer e weaned at postnatal day 18; and were tested for locomotor activity at pos tnatal days 20-24. Pups were sacrificed on postnatal day 36-38 and 18 discr ete brain areas were analyzed for [I-125]alpha-bungarotoxin (alpha-BT) bind ing by quantitative autoradiography. Prenatal nicotine caused an elevation in locomotor activity (vertical movements) in offspring. [I-125]alpha-BT bi nding was significantly reduced in the hippocampal CA1 region (29%), dentat e gyrus (22%). and medial geniculate nucleus (29%). These Endings suggest t hat some of the behavioral abnormalities induced by prenatal nicotine expos ure may be due to a reduction of alpha(7) nicotinic receptors in discrete b rain regions. (C) 2000 Elsevier Science Inc.