Abstract

Tissue handling of catecholamines has been investigated on the basis of determinations of tissue levels in rat hearts and salivary glands. Bilateral suprarenal demedullation did not alter the tissue levels. Chronic superior cervical gan glionectomy led to the disappearance of norepinephrime but not of epinephrine from the salivary glands. Combining these two procedures resulted in disappearance of both amimes.

Injection of epinephrine or norepinephrine into demedullated animals caused a marked increase in the content of the corresponding amine in the heart and salivary glands and a decrease in the concentration of the other, indicating decreased synthesis, or more probably, displacement of endogenous catecholamine. Most of the increase in salivary glands following injection was prevented by chronic superior cervical ganglionectomy, which limited the catecholamine content to the equivalent of the epinephrine level in denervated glands from animals with intact suprarenals.

It is concluded that epinephrine and norepinephrine can be accumulated from the bloodstream and stored in tissues other than those in which they were synthesized. Most of the accumulation is in tissue sympathetic nerve endings, which have a storage capacity considerably greater than their normal catecholamine content. Quantitative aspects of this uptake suggest that it may play an important role in terminating the actions of exogenous and particularly those of endogenous catecholamines.