| Abstract: | Assessed the influence of test environment on the expression of hyperactivity produced by neonatal 6-hydroxydopamine (6-OHDA) administration in Sprague-Dawley rat pups at 15, 19, and 22 days of age in 3 experiments. The 6-OHDA Ss and an equal number of controls were tested in isolation, mixed groupings of 2 treated and 2 control pups, mixed groupings with their anesthetized mothers, mixed groupings with an anesthetized sibling, and homogeneous groupings of all treated and all control siblings. Social factors had differential effects on activity, particularly at 19 days of age: the 6-OHDA Ss were hyperactive relative to controls in isolation, and both treated and control pups were equally active in the mixed grouping and were hyperactive relative to control isolation levels. The addition of an anesthetized mother sharply attenuated the activity of both types of pups. It is concluded that social factors strongly influenced the behavior of rat pups with whole brain dopamine depletion produced by 6-OHDA and, within the confines of this animal model of hyperactivity, exerted greater attenuating effects on their activity than previously observed with stimulant medication. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
