Abstract
Incubation of striatal slices in high potassium media or in media containing 1 mM dibutyryl-cAMP results in an increase in the activity of tyrosine hydroxylase. Both treatments require a period of time before maximal activation is attained, and once activated, the activated tyrosine hydroxylase has a similar time course of inactivation The activation of tyrosine hydroxylase produced by potassium depolarization is calcium dependent while the activation produced by dibutyryl-cAMP is independent of the presence of calcium in the medium. The activation produced by depolarization is additive with the activation produced by dibutyryl-cAMP. The pH optima for the tyrosine hydroxylase isolated from the striatal slices exposed to high potassium differs substantially from the tyrosine hydroxylase obtained from slices incubated with dibutyryl-cAMP. This difference is not due to changes in the amount of dopamine present in the striatal extracts. These observations suggest that the activation of tyrosine hydroxylase produced by depolarization and that produced by cAMP probably occur by different processes.
ACKNOWLEDGMENTS We thank Ms. Anne Morrison for her excellent technical assistance.
- Copyright © 1979 by Academic Press, Inc.
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