Catecholamines classification

Furchgott, R. F. (1972). The classification of adrenoreceptors (adrenergic receptors) An evaluation from the standpoint of receptor theory. In Handbook of experimental pharmacology, catecholamines, Vol. 33, edited by H. Blaschko and E. Muscholl, pp. 283—335. Springer-Verlag, Berlin. 

The distinction between a- and P-adrenergic receptors was first proposed by Ahlquist in 1948 based on experiments with various catecholamine derivatives to produce excitatory (a) or inhibitory (P) responses in isolated smooth muscle systems. Initially, a further subdivision into presynaptic a2- and postsynaptic oq-receptors was proposed. However, this anatomical classification of a-adrenergic recqrtor subtypes was later abandoned. 

CLASSIFICATION OF ADRENERGIC RECEPTORS Understanding the diverse effects of the catecholamines and sympathomimetic agents requires understanding the properties of the different types of adrenergic receptors and their distribution on various tissues and organs (Tables 6-1,... 

Adrenergic receptors are located throughout the body on neuronal and non-neuronal cells where they mediate a diverse range of responses to the endogenous catecholamines adrenaline and noradrenaline. To date, nine adrenergic receptors have been cloned. The classification of epinephrine receptors into a-receptors and P-receptors stems from Ahlquist (1948). Epinephrine and five related substances in a number of bioassays acted in either an excitatory or an inhibitory manner. The results could only be explained by postulating two different receptors, i.e. the a- and the P-receptors. 

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