[The distribution of serotonin 5-HT1A receptors in the brain of rats genetically predisposed to the development of catalepsy].

[3H]-8-OH-DPAT specific binding was determined in brain regions of S40 rats selected for predisposition to freezing (catalepsy). Significant decrease in Bmax in the frontal cortex and increase in Kd in the hippocampus as well as a strong tendency to a decrease in Bmax in the midbrain and hypothalamus were shown in cataleptic rats. The findings suggest the involvement of serotonin 5-HT1A receptors in the genetic predisposition to fear-induced passive defensive response.