The "in vivo" effects of antifeins on casein kinase NII from rat brain neuronal chromatin have been investigated. Injection of antifeins into rats resulted in changed in cAMP-independent phosphorylation of HMB 14 by casein kinase NII. No changes in HMB 17 phosphorylation were found. Casein kinase NII was isolated and purified from rat brain neuronal chromatin. It was established that casein kinase phosphorylates HMG 14 (but not HMB 17) from rat rain cells and calf thymus as effectively as do exogenous substrates, phosvitin and casein. The Km values for HMB 14 and HMB 17 from brain cells are 5.1 and 180.5 mumol, respectively. Antifeins do not influence casein kinase NII, when HMB 17, phosvitin and casein are used as substrates. HMG 14 phosphorylation changed significantly under the action of antifeins (10(-8)-10(-6) M). "In vivo" and "in vitro", some antifeins increase, and others reduce phosphorylation of HMB 14 by casein kinase NII. This correlates with their action on the transcription and long-term memory. The role of casein kinase NII and its physiological substrates in regulation of chromatin transcription is discussed.