BRAIN SECONDARY MESSENGER SYSTEMS IN RATS OF DIFFERENT STRAINS IN NORMAL CONDITIONS AND NEUROTIZATION

Cyclic nucleotide phosphodiesterase (PDE) activity and calmodulin (CaM ) content were studied in brain regions of rat strains selected for ex citability of the nervous system (low and high threshold of excitabili ty, Lt and Ht), Wistar and rat strain with genetic catalepsy (GC). PDE activity differences were found to be between GC and Wistar in cortex , hypothalamus and amigdola; between Lt and Ht, in striatum. CaM conte nt differences were between Lt and Ht in hippocampus. Neurotization le d to (1) the increase of PDE activity in cortex and hippocampus of Ht rats; (2) the decreas of PDE activity in Lt hypothalamus; (3) the incr ease of CaM content in Ht hippocampus; (4) the decrease of CaM content in cortex and hippocampus of Lt rats. The results suggest the existen ce of genetic links between the excitability of the nervous system, se condary messenger system and behaviour.