Formation of a persistent inhibitory state of brain adenylate cyclase by GTP analog: Regional differences.
Inhibition of adenylate cyclase by pretreatment with guanyl-5?-ylimidodiphosphate (10 ?M) at 0 degrees C was examined in particulates obtained from 8 non-neural tissues and from various areas of the CNS of the guinea pig. The excess of the GTP analog used for the pretreatment was removed by washing prior to the enzyme assay. Under these conditions, adenylate cyclase from all the non-neural tissues was activated or not altered while that from the brain was persistently inhibited with kinetics properties similar to those reported previously (Yamamoto and Shimizu, 1983). In the CNS, in general, the inhibition was more marked in those areas containing high densities of neuronal plasma membrane (cerebral cortex, cerebellum, hippocampus) than in areas consisting predominantly of myelin and glial cells (pons, medulla, spinal cord). The formation of a persistently inhibitory state presented herein represents one of the properties specific to brain adenylate cyclase.
Yamamoto
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T
Laboratory of Cell Physiology, Department of Life Chemistry, Graduate School at Nagatsuta, Tokyo Institute of Technology, Yokohama, Japan.
Shimizu
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H