β1-and β2-adrenoceptors in hippocampal CA3 region are required for long-term memory consolidation in rats

• β1-AR is required for the hippocampus dependent memory consolidation.
• β2-AR is involved in the hippocampus dependent memory consolidation.
• The expression of β1-AR is increased during the consolidation of contextual fear memory.

The existence of β-adrenoceptors (ARs) in the hippocampus and the importance of β-ARs in regulating synaptic plasticity and learning/memory function are well documented. As known, β-ARs in area cornu ammonis 1 (CA1) are involved in regulating memory consolidation. However, little is known about the functional roles of the β-ARs subtypes, β1- and β2-ARs, in the hippocampal cornu ammonis 3 (CA3) region. To address this question, we firstly locally infused the β1- or β2-ARs antagonist into the CA3 region and observed that blockage of either β1-AR or β2-AR impaired long-term contextual fear memory and water-maze spatial memory. We also found that, following the contextual fear conditioning, the expression of β1-AR in the CA3 region significantly increased, whereas β2-AR was unchanged. Then intra-CA3 infusion of recombinant lentiviral RNAi vectors for β1 or β2-ARs also produced deficit in contextual memory consolidation. Taken together, the results suggested that the β1- and β2-ARs in the CA3 region were involved in hippocampus dependent memory consolidation.