Evidence of Active-Forgetting Mechanisms? Blocking Arachidonic Acid Release May Slow Forgetting of Sensitization in .

Long-term sensitization in is accompanied by a persistent up-regulation of mRNA encoding the peptide neurotransmitter Phe-Met-Arg-Phe-amide (FMRFa), a neuromodulator that opposes the expression of sensitization through activation of the arachidonic acid second-messenger pathway. We completed a preregistered test of the hypothesis that FMRFa plays a critical role in the forgetting of sensitization. received long-term sensitization training and were then given whole-body injections of vehicle (= 27), FMRFa (= 26), or 4-bromophenacylbromide (4-BPB; = 31), a phospholipase inhibitor that prevents the release of arachidonic acid.