Activity-dependent release of endogenous adenosine modulates synaptic responses in the rat hippocampus

摘要: Adenosine is a potent inhibitory modulator of synaptic transmission in the CNS, but its role normal physiological function unclear. In present experiments, we have found electrophysiological evidence for activity-dependent release adenosine from hippocampal slices evoked by physiologically relevant stimulation, and demonstrated that this modifies activity brain region. When two independent excitatory pathways to CA1 pyramidal neurons are used evoke field EPSP responses, prior activation one pathway will inhibit via other input. This inhibition can be antagonized nonselective receptor antagonist theophylline, selective A1 8-cyclopentyltheophylline, suggesting response due endogenous activates presynaptic release-modulating receptors. observed following single stimulus conditioning pathway, although it more pronounced when train pulses used, maximal 16-32 stimuli (at 100 Hz). four appears with latency approximately 50 msec, peaks 200-250 msec train, recovers baseline between 1 2 sec. Further mediated provided observation superfusion dipyridamole (an uptake inhibitor), deaminase inhibitor erythro-(2-hydroxy-3-nonyl)adenine, enhanced both duration amplitude inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)