Effect of thyroxin on behavior of mice with inherited difference in predisposition to catalepsy

We studied effects of chronic thyroxin administration (2 mg/l, for 60 days) on motor activity, anxiety and depression-like behavior in cataleptic (ASC/Icg) and non-cataleptic (AKR/J) strains of mice. No effects of thyroxin on anxiety indicators in "open field" and "light/dark" tests were revealed in mice of the strains under study. At the same time, thyroxin increased moveability in the "open field" test in AKR/J mice and produced an antidepressant effect in the "forced swimming" test in animals from ASC/Icg strain. Obtained results are indicative of the role of inherited predisposition to catalepsy in determining the sensitivity to thyroid hormones.