CAMKII inhibition in the parabrachial nuclei elicits conditioned taste aversion in rats

The conditioned taste aversion (CTA) paradigm was used to assess the role o f Ca2+/calmodulin-dependent protein kinase (CAMKII) in associative learning . KN62, a specific inhibitor of CAMKII, was injected into the parabrachial nuclei (PBN) either immediately after saccharin drinking (CS) or after sacc harin drinking and i.p. injection of LiCl (US). Injection of KN62 into the PEN after saccharin drinking elicited clear CTA (Exp. 1). This effect was d osage-dependent and site-specific (Exp. 2). The results are discussed in re lation with an earlier report showing that CTA acquisition is disrupted by injection of Ca2+/phospholipid-dependent protein kinase (PKC! inhibitor che lerythrine into the PBN during CS-US interval. It is suggested that the pri ncipal serine/threonine kinases play different roles in CTA learning: where as PKC activity is necessary for the gustatory short-term memory formation, CAMKII acts similarly to the US itself-an unexpected role of CAMKII in ass ociative learning, (C) 2001 Academic Press.