Abstract
Addition of adenosine or its nucleotides to the medium immediately decreased the amplitude of postsynaptic potential (N-wave) and enhanced the formation of 14C-cyclic AMP from prelabelled ATP pool in the olfactory cortex slices of guinea pig. After a removal of the agents, the inhibition on the potential was rapidly recovered and the amount of cyclic AMP was diminished back to the original level. Theophyline inhibited both effects of the agents. The physiological roles of adenosine and adenine nucleotides were discussed in view of a possibility of neurotransmitters or modulators in CNS as well as the mediation of their action through cyclic AMP.