A simple procedure for distinguishing dopamine from noradrenaline in peripheral nervous structures in the fluorescence microscope.

The difference between dopamine and noradrenaline after ordinary histofluorescent procedures cannot be discerned. Reserpine treatment results in depletion of fluorescent material from dopaminergic and noradrenergic peripheral nervous structures. Administration of reserpine, 1 mg/kg subcutaneously for 3 hr, followed by intraperitoneal injection of 200 mg/kg levodopa methyl ester on 0.9% saline for 90 min, result in refluorescence of dopaminergic (glomus cells of the carotid body) but not noradrenergic (sympathetic ganglion cells, nerves of atrial heart muscle and blood vessels) structures. Hence, the sequential administration of these readily available drugs and the application of ordinary histofluorescent techniques result in a simple procedure for distinguishing dopamine from noradrenaline in the fluorescence microscope.