Abstract

Although many details of the chemical reactions in which catechol amines are formed or destroyed remain to be elucidated, new lines of enquiry have come to the fore: these deal with the interrelations between chemical changes and spatial distribution of active substances. The adrenal medullary cell has been an object of histochemical study since the days of Vulpian and Henle; it may be hoped that the new findings will lead to an increased understanding of the mechanism by which the release of mediator is translated into secretory activity. Similarly, increased knowledge of the sites of enzymic inactivation of adrenaline and noradrenaline may pave the way for a more precise location of the sites of their biological action in the effector cell.