Abstract: The purpose of this study was to investigate the effect of microinjectionof norepinephrine (NE) into the rat hippocampal dentate gyrus (DG) on thesynaptic efficacy during the establishment and consolidation of conditioneddrinking response. Field potentials elicited by perforant path stimulation wererecorded from the DG of freely moving rats. The results were as follows:NE significantly enhanced synaptic efficacy, facilitating the development oflearning-dependent long-term potentiation (LdLTP) and the establishment ofconditioned drinking response, but no effect on retention of LdLTP was ob-served. The results indicated that NE was involved in the development ofLdLTP in the dentate gyrus.

Key words: long-term potentiation, learning, memory, hippocampus, norepinephine