Dopamine Beta-Hydroxylase Activity in the Cat Carotid Body
Dopamine beta-hydroxylase (DBH), the enzyme that catalyzes the conversion of dopamine to norepinephrine, is present within sympathetic storage vesicles (6, 12). Similar dehse-cored vesicles are found in the glomus cells of the carotid body. Glomus (7) cells store dopamine and norepinephrine (13), and thus DBH should be one of the biosynthetic enzymes present in the glomus cells. However, there also exist in the carotid body sympathetic fibers from the superior cervical ganglion, which contain norepinephrine in their dense-cored vesicles. The purpose of this work was to measure DBH activity in normal and sympathectomized carotid bodies to determine what proportion of the DBH activity corresponds to that present in the carotid body cells versus the sympathetic nerve endings. Furthermore, the possible influence of the sinus nerve endings on the DBH enzymatic activity in the glomus cells was studied by cutting the sinus nerve in sympathectomized animals.
KeywordsCarotid Body Superior Cervical Ganglion Nictitate Membrane Sympathetic Fiber Glomus Cell
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