Paul Ehrlich and his Receptor Concept

Abstract

This chapter focuses on the Berlin bacteriologist and immunologist Paul Ehrlich (1854–1915). It deals with the emergence of his receptor concept between 1878 and approximately 1905, by which time the concept was largely developed. As Ehrlich was one of the pioneers of the receptor idea, research on Ehrlich and his receptors needs to solve a basic problem: are receptors ‘objective’ facts of nature and the ‘discovery’ of the receptor somehow ‘inevitable’, or did Ehrlich ‘construct’ the receptors?¹ We will draw on the second alternative, which corresponds with the sociological constructivist interpretation of science: that discoveries do not neatly correspond to objective entities in nature; they depend decisively on the cultural setting, for example, the social position of the researcher and the local scientific system.² Ehrlich’s discovery of the receptor concept emerged from both his social and scientific backgrounds. Although the roots of his ideas can be traced back to early stages of his career, although his ideas appeared in a logical order, and although he was driven by a leitmotif throughout his academic life, it was far from clear that he would develop the receptor concept. And the receptor concept, as developed by Ehrlich, was nothing more than a hypothetical option, on the one hand vulnerable to falsification and on the other hand a prospective tool for explaining parts of the metabolism of animals and human beings. In this chapter we will concentrate on the origin of the receptor idea. Its birth and early character were rooted in problems that made the introduction of the idea in post-1945 pharmacology a surprising and unforeseeable event.