Summaries of LTP studies. A, LTP induction is dose-dependently inhibited by both ethanol and acetaldehyde. B, LTP induction in the presence of 20 mM ethanol is dese-dependently inhibited by acetaldehyde. LTP inhibition by 20 mM ethanol plus 60 μM acetaldehyde is overcome by 4MP, an ADH inhibitor, and PTX, a GABAR antagonist. C, HFS delivered 30 min after washout of 20 mM ethanol plus 60 μM acetaldehyde fails to induce LTP. APV, an NMDAR antagonist, administered with ethanol and acetaldehyde allows LTP induction in the same paradigm. * P < 0.01.