Learning-specific, time-dependent increases in hippocampal CaMKII activity and AMPA receptor.

CAMMAROTA, M., BERNABEU, R., LEVI DE STEIN, M., IZQUIERDO, I. & MEDINA, J.

JOURNAL OF NEUROCHEMISTRY

WILEY-BLACKWELL PUBLISHING, INC

Año: 1997 vol. 69 p. 233 - 235

0022-3042

Ca2+/calmodulindependent protein kinase II (CAMK II) and one of its target, amino3hydroxy5methylisoxazole4propionic acid (AMPA), glutamate receptors have been shown to participate in both longterm potentiation (LTP) in the hippocampus, and in spatial, as well as in a variety, of learning paradigms. Recently, we were able to demonstrate that the intrahippocampal infusion of a specific inhibitor of CAMK II (KN62) provoked full retrograde amnesia of an inhibitory avoidance learning in rats when given immediately, but not 120 or 240 min, after training. Furthermore, this task is accompanied by a rapid, selective and reversible increase in hippocampal [3H] AMPA receptor binding. Here we report the effect of this aversively motivated learning task on CAMK II activity, and AMPA GluR1 subunit phosphorylation and immunoreactivity in the hippocampus. One trial inhibitory avoidance training is associated with a learningspecific, timedependent increase (25-78%) in both total and Ca2+ independent activities of CAMK II in the hippocampus of rats killed immediately (0 min), but not 120 min, after training. In addition, immunoblotting experiments showed an increment in the amount of the subunit of CAMK II at 0, 30 and 120 min after training. An increase in the in vitro phosphorylation of and subunits of CAMK II was also observed in hippocampal synaptosomal membranes (SPM) of trained rats killed immediately and 30 min posttraining.