Long-term hypoxia increases the turnover of dopamine but not norepinephrine in rat sympathetic ganglia.

The content and turnover of dopamine, 3,4-dihydroxyphenylacetic acid and norepinephrine have been investigated in the superior cervical, coeliac and mesenteric ganglia of rats exposed to moderate normobaric hypoxia (10% O2 in N2) lasting for 2-28 days. the turnover was estimated by the decrease in amine contents after inhibition of catecholamine biosynthesis with alpha-methyl-p-tyrosine. In all 3 sympathetic ganglia, long-term hypoxia elicited a sustained increase in the content and turnover of dopamine. In contrast, the content and turnover of norepinephrine remained unchanged, except for a moderate increase in the coeliac ganglion after 14 and 28 days of hypoxia. These results suggest that the dopamine and norepinephrine pools in ganglia have a different functional significance and that rat sympathetic ganglia contain a pool of dopamine specifically sensitive to long-term hypoxia.