Reports

Catecholamine Biosynthesis in Brains of Rats Treated with Morphine

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Science  15 May 1970:
Vol. 168, Issue 3933, pp. 854-856
DOI: 10.1126/science.168.3933.854

Abstract

In the brains of rats without tolerance to morphine, the accumulation of [14C]dopamine formed from [14C]tyrosine injected intracisternally is increased, reaching a maximum in the hypothalamus and striatum 1 hour after administration of morphine. In tolerant rats, the rate of incorporation of carbon-14 into dopamine and into norepinephrine in these areas is more than twice that in animals that have received only one injection of morphine.