A specific sympathomimetic ergone in adrenergic nerve fibres (sympathin) and its relations to adrenaline and nor-adrenaline.

Noradrenaline shown to be the predominant transmitter of the effects of sympathetic nerve impulses.

In 1970 Euler shared the Nobel Prize in Physiology or Medicine with Katz and Axelrod "for their discoveries concerning the humoral transmitters in the nerve terminals and the mechanism for their storage, release and inactivation."