Sinoaortic denervation changes catecholamines in caudate-putamen of rats.

The 3-day sinoaortic-denervated (SAD) rat has a reduced concentration of dopamine (DA) in caudate-putamen (CP) (Brain Research, 299 (1984) 380-383). This suggested that the nigrostriatal system processes input from the cardiovascular system via arterial baroreceptor pathways. In this study we compared regional DA levels in CP of SAD and sham-operated (SO) rats 3 and 7 days after surgery. Bilateral CP samples were obtained by micropunch from consecutive frozen brain sections. Samples were taken throughout the entire length of CP from dorsal, lateral and ventral areas. Punches of two consecutive sections were pooled and assayed for DA and norepinephrine (NE). SO rats showed a rostro-caudal gradient of DA in all 3 areas. Three-day SAD rats had significantly lower cumulative DA concentrations in each of the 3 CP areas. The concentrations in each region of the 3 areas were also reduced and about half of them achieved statistical significance. SO rats did not show a gradient of NE. Cumulative NE was significantly lower in dorsal and ventral areas of SAD rats. In 7 days SAD rats, DA values were no longer reduced, but were significantly elevated in dorsal but unchanged in ventral areas. These data support evidence of nigrostriatal interaction with baroreceptor pathways.