J. Tonkiss et al., DIFFERENTIAL-EFFECTS OF PRENATAL PROTEIN-MALNUTRITION AND PRENATAL COCAINE ON A TEST OF HOMING BEHAVIOR IN RAT PUPS, Physiology & behavior, 60(3), 1996, pp. 1013-1018
The effects of prenatal cocaine exposure and protein malnutrition on o
rientation to home nest material was assessed in rat pups. Sprague-Daw
ley darns were fed a dib of low protein content (6% casein), an isocal
oric diet of adequate protein content (25% casein, control), or a labo
ratory chow diet prior to mating and throughout pregnancy. Within each
diet group, rats received either cocaine injections (30 mg/kg IP 2 ti
mes per week prior to mating and then 30 mg/kg SC daily from day 3 to
18 of pregnancy) or saline injections. All litters were fostered on th
e day of birth to control mothers fed an adequate diet. On postnatal d
ays 7, 9, and 11, a single pup from each litter (n = 11-15 per treatme
nt) was tested repeatedly in a clean test cage for the rapidity of app
roach, and level of attraction to their own home (nest) bedding compar
ed with fresh bedding. Prenatal malnutrition and prenatal cocaine expo
sure each gave rise to independent effects on performance, based upon
factor analysis. Prenatal malnutrition, but not prenatal cocaine, incr
eased the time taken for rat pups to approach their nest bedding, redu
ced the time spent on this bedding, decreased the number of entries in
to the sector containing the home bedding and reduced pup weight. Pren
atal cocaine, but not prenatal malnutrition, produced a reduction in a
ctivity, but had no effect on pup weight. The lower activity level was
most pronounced on postnatal day 7. Surprisingly, interactive effects
of prenatal cocaine and prenatal malnutrition were not observed on an
y behavior examined. Nevertheless, the co-existence of drug addiction
and malnutrition in human populations raises the possibility that some
of the effects generally attributed to drug exposure may, in fact, be
due to malnutrition.