Catecholamine metabolism in morphine withdrawal in the dog.

Abstract

I HAVE noted1 a decrease in the catecholamine content of the rat brain after withdrawal of chronic administration of morphine. This finding, however, seemed to be confined to a certain strain of rats with very conspicuous abstinence symptoms, while an increased urinary excretion of adrenaline and nor-adrenaline2 was observed in three different rat strains. For studies of abstinence phenomena of the excitatory type, comparable with those found in man, higher species must be studied. In 1932 Tachikawa3 reported an increased amount of ‘adrenaline’ in the blood of chronically morphine-treated dogs when the drug was withheld. In 1960 and 1961 Maynert and Klingman4,5 reported a decrease of brain and adrenal catecholamines in morphine-tolerant dogs and rabbits when an abstinence syndrome was produced by nalorphine. No numerical data were given for the decrease.