Blockade of hippocampal long-term potentiation by sustained tetanic stimulation near the recording site.
Specific patterns of electrical stimulation trigger several forms of synaptic plasticity in hippocampal pyramidal cells, including a long-term potentiation (LTP) of excitatory synaptic transmission. I investigated the effect of commonly used stimulation protocols at different distances from the recording site. Sustained electrical stimulation (100 Hz, 1 s) delivered close to the recording site prevented LTP induction; the same stimulation from a second electrode placed farther away subsequently produced LTP at the same recording site. Strong stimulation near the recording site could also interfere with LTP triggered from a distal site. In contrast to sustained high-frequency stimulation, intermittent stimulation (theta burst pattern) delivered close to the recording site produced normal LTP. These data support the hypothesis that strong stimulation releases a factor that acts locally to prevent LTP.
Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
J A
JA
Kauer
D000818:Animals; D004558:Electric Stimulation; D004566:Electrodes; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors