ON THE ROLE OF BRAIN-SEROTONIN IN EXPRESSION OF GENETIC PREDISPOSITION TO CATALEPSY IN ANIMAL-MODELS

The activity of the rate-limiting enzyme of serotonin biosynthesis, tr yptophan hydroxylase, in the striatum but not in the hippocampus and m idbrain of rats bred for predisposition to catalepsy was higher than i n nonselected rats, Mice of the highly susceptible to catalepsy CBA st rain also differed from other noncataleptic mouse strains by the highe st tryptophan hydroxylase activity in the striatum, Inhibition of tryp tophan hydroxylase with p-chlorophenylalanine and p-chloromethamphetam ine drastically decreased immobility time in hereditary predisposed to catalepsy animals, A decrease in the H-3-ketanserin specific binding in the striatum of cataleptic rats and CBA mice was found. It was sugg ested that this decrease in 5-HT2A serotonin receptor density represen ted a down regulation of the receptors due to an activation of seroton ergic transmission in striatum, It is suggested that hereditary catale psy may be resulted from genetic changes in the regulation of serotoni n metabolism in striatum. (C) 1995 Wiley-Liss, Inc.