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DEVELOPMENTAL AND REGIONAL VARIATIONS IN NEUROTRANSMITTER‐SENSITIVE ADENYLATE CYCLASE SYSTEMS IN CELL‐FREE PREPARATIONS FROM RAT BRAIN
Author(s) -
Hungen K. Von,
Roberts S.,
Hill Diane F.
Publication year - 1974
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1974.tb04299.x
Subject(s) - medicine , endocrinology , cyclase , adenylate kinase , dopamine , hindbrain , cerebral cortex , striatum , neurotransmitter , norepinephrine , midbrain , cerebellum , central nervous system , hippocampus , biology , chemistry , receptor , stimulation
Investigations have been carried out on regional and developmental variations in the properties of adenylate cyclase systems in participate preparations from rat brain. EGTA was routinely included in the assay medium to minimize differences in the state of activation of these systems resulting from variations in their exposure to endogenous Ca 2+ . At birth, adenylate cyclase activity was much higher in the hindbrain‐medullary preparations than in comparable fractions from cerebellum, cerebral cortex or subcortex (including midbrain, corpus striatum, hypothalamus and hippocampus). Adenylate cyclase activity increased during early development in preparations from all areas of the brain. Maximal levels were reached at 14 days of age or later. These levels were not greatly altered in the young adult animal, except in the hindbrain‐medullary area, where a decrease in activity was observed. Adenylate cyclase systems in cerebral cortical and subcortical preparations were activated by norepinephrine and dopamine throughout development. Serotonin also stimulated adenylate cyclase activity in these preparations from young animals but was much less effective in comparable fractions from adult rats. The response to dopamine was diminished with age in cerebral cortical preparations, but not in subcortical fractions. The responses to norepinephrine increased in both brain regions during early development. Adenylate cyclase systems in particulate preparations from the cerebellum and hindbrain‐medullary areas exhibited relatively poor responses to the biogenic amines. Detailed studies of the properties of the cerebral cortical adenylate cyclase systems revealed enhancement of activity by Ca 2+ and F − at all stages of development with the maximal activation at 2–3 weeks of age. The results suggest that developmental differences in hormonal sensitivity of adenylate cyclase systems from diverse areas of the brain are related to changes in the proportions of the receptor‐enzyme complexes responsive to the different biogenic amines.