BEHAVIORAL-EFFECTS OF PRENATALLY ADMINISTERED SMOKELESS TOBACCO ON RAT OFFSPRING

Two dosages of Smokeless Tobacco (ST) extract were given to gravid Spr ague-Dawley rats by oral gavage on gestational days (GD) 6-20. The low dosage contained ST ''tract equivalent to 1.33 mg/kg nicotine (STD-1) , and the high dosage contained ST extract equivalent to 4.0 mg/kg nic otine (STD-2). Dams were dosed three times daily at 8 a.m., 11 a.m., a nd 2 p.m., thus providing total daily nicotine equivalent dosages of 4 mg/kg/day and 12 mg/kg/day. Controls received equivalent amounts of d istilled water by gavage. Dams were allowed to deliver and all experim ental pups were fostered to control mothers. On postnatal day 1 (PND 1 ) litters were culled to 4 +/- 1 females and 4 +/- 1 males. Weights, p hysical landmark development, and behavioral performance of pups were monitored during pre- and post-weaning periods. Behavioral tests inclu ded: surface righting, negative geotaxis, swimming development, open-f ield activity, active avoidance in shuttle box, and Cincinnati swimmin g maze. Our results show that the STD-2 dose resulted in reduced mater nal weight gain. Offspring weights were reduced in a dose-related mann er, with the most consistent weight deficits seen in the STD-2 group u ntil PND29. Consistent STD-1 weight deficits were seen up to PND 8. Th e incidence of deaths was increased in the STD-2 dosage group. No sign ificant treatment-related differences were observed in development of physical landmarks. Male STD-2 pups righted faster than controls, and significant differences were noted in swimming development with the ST D-1 group of pups performing less effectively than controls. Activity levels, assessed during both pre- and post-weaning periods were not af fected. No treatment-related differences were seen in the active avoid ance shuttle box or Cincinnati swimming maze tests, which assessed lea rning. Female brain weights were reduced in the STD-1 treatment group.