Release of proteins during long-term potentiation in the hippocampus of the anaesthetized rat.

Using a push-pull device, the release of endogenous proteins in the extracellular space was investigated in the CA1 region of the hippocampus of anaesthetized rats. With low-frequency stimulation of the Schaffer collaterals, there was a relatively stable release of 5 proteins (64, 54, 48, 45 and 16 kDa). A train of high-frequency stimulation produced a long-lasting enhancement of the negative field EPSP and a delayed (90-120 min) enhancement of the release of these proteins. An additional 19 kDa protein was present only 90 min after the train. These observations raise the possibility that release of proteins might be involved in the maintenance of LTP.