Effect of bromophenacyl bromide, a phospholipase A2 inhibitor, on the induction and maintenance of LTP in hippocampal slices

The effect of bromophenacyl bromide (BPB), a phospholipase A₂ (PLA₂) inhibitor, on both the induction and the maintenance of long-term potentiation (LTP) was investigated in field CA₁ of the hippocampal slice preparation. One hour of BPB application (50 μM) caused a large reduction in the magnitude of LTP induced by a theta burst stimulation (TBS) paradigm. BPB had no significant effect on either the degree of paired-pulse facilitation or the amount of pre-established LTP. Furthermore, the facilitation of postsynaptic responses occuring during TBS and in the first minute following TBS was not reduced by the PLA₂ inhibitor. These results indicate that the inhibition of LTP produced by BPB is not due to an effect of the drug on a physiological event that triggers LTP. The data also suggest that PLA₂ activation plays a critical role in the expression of LTP, but is not required for the maintenance of the potentiation.