We have shown previously that activation of mGlu receptors using a group I specific mGlu receptor agonist, (RS)-3,5-dihydroxyphenylglycine (DHPG), can induce long-term depression (LTD) in the CA1 region of the hippocampus (Palmer et al., 1997). We now report that DHPG-induced LTD is facilitated by treatment with KN-62, an inhibitor of certain Ca2+ /calmodulin-dependent protein kinases (CaMKs), including CaMKII. (C) 1999 Elsevier Science Ltd. All rights reserved.