Anisomycin inhibits the late maintenance of long-term depression in rat hippocampal slices in vitro.

Studies were performed to investigate whether electrically-induced long-term depression (LTD) within rat hippocampal slices in vitro shares any common cellular features with LTD in the intact animal, with particular emphasis being placed on mechanisms required for its late maintenance. Our initial studies have led to the development of stimulation protocols which are able to reliably produce different forms of LTD. Depending on the induction protocol applied, we are able to demonstrate a transient protein synthesis-independent early-LTD with a duration of up to 3-4 h, together with a de novo protein synthesis-dependent late-LTD lasting for at least 8 h. Furthermore, we are able to show input-specific LTD within the CA1 region, with expression shown only by those synapses specifically stimulated by a low-frequency protocol. These studies are important pre-requisites to investigate mechanisms of 'synaptic tagging' and 'late-associativity' during LTD.