Abstract
IT is now generally accepted that α-methyldihydroxyphenylalanine (α-methyldopa) is an effective means of lowering the blood pressure in cases of hypertension. The mechanism of its action, however, is by no means clear. One of the known actions of α-methyldopa is the inhibition of the enzyme dopadecarboxylase, and, as this enzyme is involved in the synthesis of noradrenaline, it was thought that its inhibition could explain the lowering of the blood pressure. It was found1,2 that α-methyldopa caused depletion of noradrenaline in the brain and heart, and at first this seemed to support the ideas about its hypotensive action. The duration of tissue noradrenaline depletion was, however, far greater than the duration of the dopadecarboxylase inhibition and the lowering of blood pressure. Furthermore, stronger decarboxylase inhibitors than α-methyldopa do not cause a lowering of blood pressure in hypertensive patients3. Animal experiment has shown4 that, despite noradrenaline depletion of tissues, α-methyldopa does not interfere with the effects of sympathetic nerve stimulation.
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DAVIES, B. α-Methyldihydroxyphenylalanine and Release of Noradrenaline. Nature 210, 957–958 (1966). https://doi.org/10.1038/210957a0
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DOI: https://doi.org/10.1038/210957a0
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