Kindling alters the calcium/calmodulin-dependent phosphorylation of synaptic plasma membrane proteins in rat hippocampus.

Abstract

Septal killing was associated with an inhibition of the post hoc phosphorylation of several synaptic plasma membrane proteins of rat hippocampus. In control rats, the 32P incorporation into proteins of MW 50,000, 58,000 and 60,000 was markedly stimulated by combined Ca/calmodulin, whereas in kindled animals, the response to combined Ca/calmodulin was reduced. Ca alone, cAMP or cGMP modulated 32P incorporation into several synaptic plasma membrane proteins but did not differentiate control from kindled tissues. Both control and kindled rats showed nonspecific inhibition of Ca/calmodulin-stimulated phosphorylation of the post hoc assay by corticotropin and by [Leu]enkephalin. The differences between control and kindled animals were most striking in hippocampus and in the amygdaloid-entorhinal area; less pronounced in cortex, basal ganglia and brain stem; and not significant in cerebellum, a region where kindling cannot be elicited. An 8-wk period of rest after kindling did not reduce these changes, suggesting that they may be as persistent as the kindling behavior itself.