Cretinism in Rats: Enduring Behavioral Deficit Induced by Tricyanoaminopropene

Rats reared on diets containing tricyanoaminopropene, the antithyroid compound that stimulates RNA synthesis, showed a deficit in performance on automated closed-field maze tests many weeks after discontinuation of the drug. The rats were also tested while still receiving the drug, and performance deficits were indicated in tests of Y-maze reversal and manual closed-field maze performance; rats treated with the drug and with thiouracil behaved in a highly similar fashion on several tasks. No evidence of facilitation by tricyanoaminopropene appeared in any of the eight learning situations used. Exposure to tricyanoaminopropene before and after birth, at doses sufficient to produce anatomical cretinism, apparently induces an enduring behavioral deficit which is similar to that of neonatal thyroidectomy-induced cretinism in rats and which parallels the mental retardation associated with human cretinism.