Effect of perinatal polybrominated biphenyl exposure on acquisition and performance of an autoshaping paradigm.

Pregnant Sprague-Dawley rats received oral doses of 0, 0.2 or 2 mg/kg/day polybrominated biphenyls (PBB) as fireMaster BP-6 (BP-6) from day 6 of gestation through day 24 postpartum. At approximately 6 months of age male and female offspring were food-deprived to 80% of their free-feeding weights and subjected to four phases of an autoshaping paradigm. Acquisition of Phase I, a VI-90 second schedule of responding, was significantly delayed for female offspring from dams administered 2 mg/kg/day BP-6; a trend toward delayed acquisition was observed in all other PBB-exposed animals. No BP-6-related difference in latency to respond during this phase was observed. Male offspring from dams administered BP-6 appeared to acquire Phase II responding (a FI-90 second contingency) at a faster rate than did control males. In contrast, BP-6-exposed females acquired Phase II responding at a somewhat slower rate than did control females. The sex-related difference in responding may involve a rate-dependent influence, as control females acquired Phase II responding much more quickly than did control males. Control males and females acquired Phase III (FR-20 responding) at approximately the same rate. No BP-6-related deficits were observed during the initial few days of acquisition of FR-20 responding. However, BP-6-exposed male offspring tended to respond more than did control males after this time. BP-6-exposed females tended to respond less than did control females only as the responding of controls approached an asymptote. Phase IV involved FR-20 responding following challenge with d-amphetamine or chloral hydrate; no significant BP-6-related changes in disruption of this behavior were observed.