| Abstrakt: |
In renal hypertensive rats the cerebral concentration of α-methyldopa, α-methyldopamine, α-methylnoradrenaline, dopamine and noradrenaline as well as the blood-pressure were determined simultaneously. The antihypertensive effect followed a time course identical to that of the increase in the cerebral concentration of α-methyldopamine and of the decrease in the concentration of dopamine, whereas lowering of blood pressure on the one hand, and changes in the levels of α-methylnoradrenaline and noradrenaline, on the other, were not related to each other. Dose-response relationships showed the same correlations and lack of correlations, respectively. These results suggest that non-β-hydroxylated catecholamines play a major role in mediating the antihypertensive effect of α-methyldopa or, alternatively, that only the newly biosynthesized α-methyl-noradrenaline is effective in lowering blood pressure. [ABSTRACT FROM AUTHOR] |
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