Journal of Neuroscience, Vol 9, 2374-2381, Copyright © 1989 by Society for Neuroscience
Evidence for transsynaptic regulation of calmodulin-dependent cyclic nucleotide phosphodiesterase in cerebellar Purkinje cells
CD Balaban, ML Billingsley and RL Kincaid
Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania 15213.
Calmodulin-dependent phosphodiesterase (CaM-PDE) is selectively expressed
in specific neuronal populations in adult rat brain. In cerebellar cortex,
it is expressed at high levels in Purkinje cells (soma and dendrites).
Climbing fiber ablation by intraperitoneal injections of 3-acetylpyridine
resulted in a selective depression of cerebellar CaM-PDE expression using
Western immunoblot procedures; neither calcineurin (calmodulin-dependent
protein phosphatase) nor other calmodulin binding proteins, detected by
biotinylated calmodulin overlays, were affected. Immunocytochemical
staining of cerebellum revealed a loss of detectable CaM-PDE
immunoreactivity in Purkinje cells, with no appreciable change in
calcineurin immunoreactivity. Cerebral cortex was examined as a control for
a direct effect of 3- acetylpyridine on CaM-PDE expression, independent of
climbing fiber deafferentation. There were no detectable changes in CaM-PDE
or calcineurin immunoreactivity in cortical pyramidal cells, and no changes
were detected, either in Western blot analyses for CaM-PDE or calcineurin
or in biotinylated calmodulin overlays. These data suggest that CaM-PDE
expression in Purkinje cells is regulated transsynaptically by climbing
fiber inputs.