TY - JOUR
T1 - Asymptotic hippocampal long-term potentiation in rats does not preclude additional potentiation at later phases
AU - Frey, U.
AU - Schollmeier, K.
AU - Reymann, K. G.
AU - Seidenbecher, T.
N1 - Funding Information:
Acknowledgements-We are very grateful to Diana Koch and Kerstin Kaiser for their skilful technical assistance during the preparation and performance of the experiments. We thank Dr Denise Manahan-Vaughan and Ritchie Brown for the critical reading of this manuscript. Parts of this work were supported by the German BMFT, FKZ: 310258A.
PY - 1995/8
Y1 - 1995/8
N2 - Hippocampal long-term potentiation may serve as an elementary process underlying certain forms of learning and memory in vertebrates. As is the case with behavioural memory, hippocampal long-term potentiation in the CA1 region and in the dentate gyrus exhibits distinct phases. These comprise a short-term early potentiation which lasts one to three hours and is independent of protein synthesis and is characterized in general by the activation of N-methyl-d-aspartate receptors and protein kinases; and a later, longer lasting phase, which can be separated by inhibitors of protein synthesis. Here, we report that the prior induction of long-term potentiation, both in the dentate gyrus in vivo and in the CA1-region in vitro, precludes further long-term but not short-term potentiation by means of a newly delivered conditioning stimulus to a subset of the same activated synapse population during the early stage (∼ 1-3 hours post tetanus). In contrast, a subsequent, long-lasting potentiation can be induced after the establishment of the late phase of potentiation (> 4 h). Thus, the system preserves the capacity for short-term potentiation immediately after potentiation, but the capacity for the induction of longer lasting plastic changes is recovered only after about four hours. Our results demonstrate that, once long-term potentiation has been established, hippocampal neurons do not lose their capacity for functional plasticity during certain phases of the maintenance of long-term potentiation.
AB - Hippocampal long-term potentiation may serve as an elementary process underlying certain forms of learning and memory in vertebrates. As is the case with behavioural memory, hippocampal long-term potentiation in the CA1 region and in the dentate gyrus exhibits distinct phases. These comprise a short-term early potentiation which lasts one to three hours and is independent of protein synthesis and is characterized in general by the activation of N-methyl-d-aspartate receptors and protein kinases; and a later, longer lasting phase, which can be separated by inhibitors of protein synthesis. Here, we report that the prior induction of long-term potentiation, both in the dentate gyrus in vivo and in the CA1-region in vitro, precludes further long-term but not short-term potentiation by means of a newly delivered conditioning stimulus to a subset of the same activated synapse population during the early stage (∼ 1-3 hours post tetanus). In contrast, a subsequent, long-lasting potentiation can be induced after the establishment of the late phase of potentiation (> 4 h). Thus, the system preserves the capacity for short-term potentiation immediately after potentiation, but the capacity for the induction of longer lasting plastic changes is recovered only after about four hours. Our results demonstrate that, once long-term potentiation has been established, hippocampal neurons do not lose their capacity for functional plasticity during certain phases of the maintenance of long-term potentiation.
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U2 - 10.1016/0306-4522(95)00117-2
DO - 10.1016/0306-4522(95)00117-2
M3 - Article
C2 - 7675206
AN - SCOPUS:0029053787
SN - 0306-4522
VL - 67
SP - 799
EP - 807
JO - Neuroscience
JF - Neuroscience
IS - 4
ER -