Histofluorescence techniques provide evidence for dopamine-containing neuronal elements in canine kidney.

Changes induced by hydrochloric acid in the excitation spectrum of catecholamine fluorophores associated with the innervation of the canine renal vasculature show that there are neuronal elements at the glomerular vascular poles containing predominantly dopamine. In contrast, the catecholamine fluorescence in the periadventitial layer of the arcuate arteries is derived from norepinephrine. The dopamine-containing structures may represent the prejunctional counterpart to the pharmacologically identified dopamine receptors in the renal vasculature. As such, this system may be involved in the normal regulation of renal blood flow and renin release.