[Role of cAMP in regulating hippocampal neuronal reactivity in vitro].

The author studied the effect of the elevated cAMP content on the efficacy of the synaptic systems of the hippocamp. The population spike (PS) response to Shaffer collateral electric stimulation was recorded in the CA1 field. The PS amplitude served as criterion of cell reactivity. Use was made of dibutyryl-cAMP (db-cAMP), an analog of cAMP, well penetrating the membrane, and of 8-/Cl-acetylaminoethylthio/-cAMP, an inhibitor of phosphodiesterase (PDE) of irreversible action, leading to cAMP accumulation by the cell. Introduction of db-cAMP into the bath medium evoked an abrupt increase in the PS amplitude, followed by gradual diminution of the response until complete depression PDE inhibitor evoked a gradual and irreversible increase of the PS amplitude. The data suggest that the secondary messenger cAMP plays an important role in synaptic processes occurring in the hippocamp.