Elevated plasma dopamine beta hydroxylase activity in rats with neurogenic hypertension

Abstract

Increased plasma dopamine beta hydroxylase, DBH, activity has been cited as evidence of increased sympathetic function in essential hypertension. Here-to-fore, experimental hypertension in animals has been associated with normal plasma DBH activity. This study shows that rats with neurogenic hypertension, induced by sinoaortic denervation, SAD, have elevated DBH activity; the mean increase in plasma DBH measured 3 days to 11 weeks after operation was 74% higher in the SAD group than in the sham-operated, control group. DBH activity showed a positive correlation with arterial pressure. Mesentery DBH activity was inversely related to plasma enzyme activity in SAD rats, indicating sympathetic nerve terminals in mesentery are a source of plasma DBH. We conclude that plasma DBH activity is an index of increased sympathetic function since it is consistently elevated in rats with neurogenic hypertension resulting from sustained central activation of the sympathetic nervous system.