RESUMEN
Freezing reaction (catalepsy) is a natural passive defensive strategy in animals. An exaggerated form of catalepsy is a symptom of grave brain dysfunction. Catalepsy in mice was shown to be linked to the Map3k1, Il6st, Gzmk, and Hspb3 genes as potential candidates for a high predisposition to catalepsy. The study sought to test the hypothesis of an association between catalepsy and expression of these genes in the brain. Thegenes' mRNA levels were measured in the hypothalamus, hippocampus, frontal cortex, striatum, and midbrain of catalepsy-resistant AKR/J strain and catalepsy-prone strains CBA/Lac, ASC (antidepressant-sensitive cataleptic) and the congenic line AKR.CBA-D13M76C. No association between expression of any investigated genes and predisposition to catalepsy was found. At the same time, multivariate analysis revealed interactions among the expressions of Map3k1, Il6st, Gzmk, and Hspb3 genes in the brain structures. A factor analysis of all variables produced two independent factors explaining 76.2% of the total variance. The catalepsy-resistant AKR strain was distinguished from the catalepsy-prone strains CBA, ASC, and AKR.CBA-D13M76C by factor 1. It was suggested that a high predisposition to catalepsy in mice can be defined by the Map3k1, Il6st, Gzmk, and Hspb3 genes' coexpression network.