Details

Autor(en) / Beteiligte

• Schantz, Susan L.
• Seo, Byung-Woun
• Moshtaghian, Jamal
• Peterson, Richard E.
• Moore, Robert W.

Titel

Effects of gestational and lactational exposure to TCDD or coplanar PCBs on spatial learning

Ist Teil von

• Neurotoxicology and teratology, 1996-05, Vol.18 (3), p.305-313

Ort / Verlag

New York, NY: Elsevier Inc

Erscheinungsjahr

1996

Quelle

MEDLINE

Beschreibungen/Notizen

• Recently we reported that in utero and lactational exposure to specific ortho-substituted polychlorinated biphenyl (PCB) congeners resulted in a learning deficit on a delayed spatial alternation (DSA) task in female rats. In this study, spatial learning and memory was assessed following in utero and lactational exposure to coplanar PCBs or 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD). Time-mated Sprague-Dawley rats were dosed with PCB 77 (3,3′,4,4′-tetrachlorobiphenyl), 2 or 8 mg/kg/day; PCB 126 (3,3′,4,4′,5-pentachlorobiphenyl), 0.25 or 1.0 μg/kg/day; TCDD, 0.025 or 0.1 μg/kg/day; or corn oil vehicle via gavage on gestation days 10–16. Litters were culled to eight on day 2 and weaned on day 21. Beginning on day 80, one male and one female from each litter were tested on an eight-arm radial maze working memory task. The TCDD-exposed rats displayed pronounced decreases in errors relative to controls. PCB 77- and PCB 126-exposed rats showed similar, but less pronounced, decreases in errors. The same animals were later tested on a T-maze DSA task, but no differences among groups were observed. In conclusion, perinatal exposure to low doses of TCDD or structurally related coplanar PCBs appeared to facilitate acquisition of a working memory task on the radial arm maze. This effect was very different from that previously observed in rats exposed to ortho-substituted PCB congeners. The rats exposed to ortho-substituted PCBs did not differ from controls on the radial arm maze and were impaired on the T-maze DSA task. Together these findings suggest that coplanar and ortho-substituted PCBs may have different mechanisms of action on the CNS.