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1. The concentrations of cyclic adenosine 3',5'-monophosphate (cyclic AMP), measured in discrete brain areas removed from rats killed by microwave irradiation, rose transiently in most areas after the administration of morphine. The most pronounced changes, however, were found 2 h after doses of either 10 or 60 mg/kg morphine when cyclic AMP levels declined significantly in the hypothalamus, medulla and cerebellum. In morphine-tolerant rat brains there were no decreases in cyclic AMP levels. 2. Basal adenylate cyclase activity in crude nerve-ending fractions from discrete areas of rat brain was unaffected by the addition of active analgesic agonists, antagonists or inactive isomers to the assay medium in vitro, except for a nonspecific inhibition at drug concentrations of 1 mM. 3. The acute administration of morphine or levorphanol, but not dextrorphan produced transient increases in basal cyclase activity of crude nerve-ending preparations from midbrain and striatum. In morphine-tolerant rats, these changes in basal adenylate cyclase activity were no longer seen.
D H Clouet, and
G J Gold, and
K Iwatsubo
February 1972,
The Biochemical journal,
D H Clouet, and
G J Gold, and
K Iwatsubo
May 1974,
Endocrinology,
D H Clouet, and
G J Gold, and
K Iwatsubo
August 1980,
Experimental lung research,
D H Clouet, and
G J Gold, and
K Iwatsubo
January 1977,
Journal of bacteriology,
D H Clouet, and
G J Gold, and
K Iwatsubo
November 1971,
Neuropharmacology,
D H Clouet, and
G J Gold, and
K Iwatsubo
January 1976,
Transfusion,
D H Clouet, and
G J Gold, and
K Iwatsubo
December 1980,
Endocrinology,
D H Clouet, and
G J Gold, and
K Iwatsubo
September 1982,
Endocrinology,
D H Clouet, and
G J Gold, and
K Iwatsubo
December 1973,
Proceedings of the National Academy of Sciences of the United States of America,
D H Clouet, and
G J Gold, and
K Iwatsubo
April 1973,
Proceedings of the National Academy of Sciences of the United States of America,
