CORRELATION BETWEEN TRYPTOPHAN-HYDROXYLASE ACTIVITY IN THE BRAIN AND PREDISPOSITION TO PINCH-INDUCED CATALEPSY IN MICE

Pinch-induced catalepsy and activity of the rate-limiting enzyme of se rotonin biosynthesis, tryptophan hydroxylase, in brain structures have been studied in mice of six inbred strains. A pronounced predispositi on to catalepsy was found in the CBA mouse strain. It was shown that t he CBA mice had the highest tryptophan hydroxylase activity in the neo striatum compared to mice of other noncataleptic strains. The experien ce of repeated victories in intermale encounters producing highly aggr essive CBA mice resulted in the inhibition of the genetically determin ed predisposition to pinch-induced catalepsy and in the simultaneous d ecrease of tryptophan hydroxylase activity in the neostriatum down to the level found in noncataleptic mice. The inhibitor of tryptophan hyd roxylase, p-chloromethamphetamine, significantly de. creased the enzym e activity in the neostriatum of CBA mice and completely inhibited the ir genetically determined predisposition to catalepsy. These findings indicate the key role of the striatal serotonergic system in the catal epsy-inducing mechanism.