Receptors term first introduced

The idea that drags act upon receptors began with Langley in 1878 [13], who introduced the term receptive substance [14]. However, the word receptor was introduced later, by Paul Ehrlich [15, 16]. During the first half of the 20th century, several observations highlighted the critical features associated with the... 

During the mid-1970s the search for endogenous ligands for opioid receptors led to the discovery of peptides with opiate-like activity. The first opioid peptides reported were the pentapeptides leucine and methionine enkephalin (Sand 4) (7), followed shortly thereafter by dynorphin A (3 8) (260,261) and ( endorphin (51)(262). Because these peptides are structurally distinct from the alkaloid opiates, the term opioid was introduced to describe all compounds, both nonpeptide and peptide, with opiate-like activity. These mammalian opioid peptides share a common N-terminal tetrapeptide sequence, but differ in their C-terminal residues (Fig. 7.9). They also differ in... 

Sialic acid was the first virus receptor identified. Hirst and McClelland and Hare discovered that influenza virus is able to hemagglutinate and that adsorbed virus is eluted from erythrocytes on incubation at 37°C, indicating an enzymatic destruction of a receptor substance on the cells [1, 2]. When a similar enzymatic activity was subsequently detected in Vibrio cholerae cultures, the term receptor-destroying enzyme was introduced [3]. The substance released by the viral enzyme from soluble hemagglutination inhibitors was initially characterized as a carbohydrate of low molecular weight [4] and then identified in crystalline form as A-acetyl-o-neuraminic acid [5]. Thus, it was clear that the receptor determinant of influenza virus was sialic acid and that the viral enzyme was a neuraminidase. Furthermore, for the first time an important biological function of sialic acid had been identified. 

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