Significance of inter-burst interval in the induction of long-term potentiation / 西安交通大学学报(医学版)

ABSTRACT

Objective To compare the different effects of different titanic parameters on the expression of long-term potentiation (LTP) and to determine the optimal patterns of tetanizing stimulation in hippocampal CA1 area in adult male rats. Methods Four tetanic parameters of 100Hz were used in the experiment. Tetanus 1 was a short burst of stimulus composed of 60 pulses, which were divided into 5 sets, each set including 4-pulses-bursts. The inter-burst intervals are lengthened gradually, 1s, 5s, 30s, 10min in sequence. Tetanus 2 was a long burst of stimulus composed of 300 pulses in all, each burst including 20 pulses. The inter-burst interval is 2s, and tetanus 3 is also a short burst of stimulus composed of 15 bursts, each burst including 4 pulses. The inter-burst interval is 2s and tetanus 4 is a single train of burst composed of 60 pulses. The field excitatory post-synaptic potentials (fEPSPs) in hippocampal CA1 area were evoked by stimulating the Schaffer collateral fibers in the stratum radiatum and the expressions of LTP induced by the four parameters were evaluated. Results The amplitude and incidence of LTP induced by tetanus 1 were higher than those induced by the other three parameters. There was no statistical significance between the responses induced by the other three parameters. Both tetanus 1 and tetanus 3 could lead to long-lasting-LTP (LL-LTP, over 3h). Conclusion A high frequency stimulus with 200ms-inter-burst interval (theta frequency) is better in the induction of LTP in hippocampal CA1 area. A short burst of stimulus with 100Hz can evoke the expression of LL-LTP in hippocampal CA1 area.