Effects of neonatal 6-hydroxydopa on behavior in female rats

Litters of female rats were treated at birth and 48 hr later with either saline or 6-hydroxydopa (60 microgram/g, IP), were ovariectomized in adulthood and tested on a number of behavioral tasks including age of vaginal opening, sexual receptivity, open-field activity, equilibrium, and habituation to acoustic startle. Results of the open-field test indicated that the treated animals were more active overall, were more likely to enter inner segments, reared more often, and defecated less than the control animals. On a rod-balancing task, the treated animals exhibited impaired equilibrium. Treated animals were more reactive than controls in response to acoustic startle, but there were no differences between the groups in rate of habituation or sensitization to the startle stimulus. Norepinephrine content of treated animals was significantly lower than controls in the cortex, amygdala, hippocampus, and spinal cord, but higher in the cerebellum and brainstem. There was no difference between the groups in cardiac norepinephrine nor in striatal dopamine.