A Pertussis Toxin-Sensitive G Protein in Hippocampal Long-Term Potentiation

High-frequency (tetanic) stimulation of presynaptic nerve tracts in the hippocampal region of the brain can lead to long-term synaptic potentiation (LTP). Pertussis toxin prevented the development of tetanus-induced LTP in the stratum radiatum-CA1 synaptic system of rat hippocampal slices, indicating that a guanosine triphosphate-binding protein (G protein) may be required for the initiation of LTP. This G protein may be located at a site distinct from the postsynaptic neuron (that is, in presynaptic terminals or glial cells) since maximal activation of CA1 neuronal G proteins by intracellular injection of guanosine-5$^{\prime}$-O-(3-thiotriphosphate), a nonhydrolyzable analog of guanosine 5$^{\prime}$-triphosphate, did not occlude LTP.