In mouse hippocampal slices, long-term potentiation (LTP) at Schaffer collateral fiber synapses onto CA1 pyramidal cells could be induced by brief trains of 5-Hz synaptic stimulation (30 s) or by longer trains of 5-Hz stimulation (3 min) delivered during β-adrenergic receptor activation. In contrast, 5-Hz stimulation, either alone or in the presence of the β- adrenergic receptor agonist isoproterenol, failed to induce LTP at associational-commissural (assoc-com) fiber synapses onto CA3 pyramidal cells. Our results suggest that although CA3 pyramidal cells give rise to both the Schaffer collateral fiber synapses in CA1 and the assoc-com fiber synapses in CA3, the induction of LTP at these synapses may be regulated by different activity- and modulatory neurotransmitter-dependent processes.
Bibliographical noteFunding Information:
We are grateful to Dr. A. Watabe for helpful comments on an earlier version of this manuscript. This work was supported, in part, by grants from the National Institute of Mental Health (MH52876), the Esther A. and Joseph Klingenstein Fund, and the Pew Charitable Trusts. T.D.M. was supported in part by the Achievement Rewards for College Scientists program. T.J.O. is a member of the UCLA Brain Research Institute.
- Long-term potentiation