PREDISPOSITION TO CATATONIC REACTIONS, MONOAMINE-OXIDASE AND DELTA-SLEEP-INDUCING PEPTIDE IN RATS

Monoamine oxidase B activity is heightened in brain stem and hemispher es of rats of GC strain predisposed to catatonic reactions as compared to control Wistar rats, and in hemispheres of wild rats predisposed t o catatonic reactions as compared to ''normal'' wild rats. In GC rats, MAO-B was characterized by an increased maximum rate of conversion of MAO-benzylamine complex and a decreased affinity for benzylamine, wit h heightened values of V and Km in benzylamine deamination. Restraint- induced stress increased MAO-A and increased MAO-B activity in Wistar, and increased MAO-B with uncharged MAO-A activity in GC rats. Adminis tration of actinomycin D to GC rats prior to restraint normalized MAO reaction to stress, making it similar to that of Wistar rats. Circadia n changes of MAO-A and MAO-B activities in Wistar and GC rats from 9.0 0 a.m. to 11.00 a.m. were of the same direction as those induced by st ress. Administration of delta-sleep-inducing peptide (120 mu g/100g) d ecreased MAO-B activity in GC and wild catatonic rats and predispositi on to catatonic reactions.