Localization of specialized noradrenaline receptors at neuromuscular junctions on arterioles of the guinea‐pig.

Noradrenaline was applied by ionophoresis to various positions on the surface of an arteriole, and any changes in membrane potential of the arteriolar smooth muscle were recorded. 2. At a proportion of positions noradrenaline produced membrane depolarization. 3. The positions where noradrenaline produced these membrane potential changes were restricted to regions close to the sympathetic nerves which innervated the arterioles.