Regional distribution of dopamine and norepinephrine in canine cerebral arteries — effect of pre- or postganglionic sympathetic denervation

The regional distribution of dopamine (DA) and norepinephrine (NE) was investigated in dog cerebral arteries using high performance liquid chromatography with electrochemical detection. The distribution patterns of these two amines differed and there was a wide fluctuation in the ratio between the amounts of DA and NE. The ratios of DA to NE in the anterior cerebral artery and the anterior inferior cerebellar artery were 2–4 times higher than in the basilar or middle cerebral arteries, thereby suggesting that DA plays a role other than that of precursor of NE. The concentrations of both amines following pre- or postganglionic sympathetic denervation (superior cervical ganglion) were investigated. After preganglionic denervation (decentralization), neither amine showed significant changes in concentration. Postganglionic denervation one week prior to sacrifice resulted in a reduction in the concentrations of both amines; however, decrease in the former was less. These results suggest that the origin of dopamine in the cerebral arteries differs from that of the sympathetic nerves, via the superior cervical ganglion.