[New concepts on central regulation of the blood pressure. Mode of action of clonidine and alpha-methyl DOPA (author's transl)].
A review is presented of several reports which strongly indicate that the reaction pattern of "cardiovascular depression" (decrease in blood pressure, heart rate and cardiac output) is triggered off by the stimulation of alpha-adrenoceptors in the brain. The efferent information is mediated by an inhibition of the sympathetic and by an activation of the cardiac vagal system. The central alpha-adrenoceptors, which are localized within the medulla, are stimulated by the antihypertensive agents clonidine and alpha-methyl-DOPA, and also by central administration of other sympathomimetic drugs such as naphazoline, oxymetazoline, amphetamine and others. It can be assumed  that these drugs mimic the action of endogenous nor-adrenaline, which is present in considerable amounts in the brain stem, and which might, under physiological conditions, mediate the pattern of cardiovascular depression.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D003000:Clonidine / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008750:Methyldopa / Q000494:pharmacology* / Q000627:therapeutic use; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011942:Receptors, Adrenergic, alpha; D013564:Sympathetic Nervous System / Q000187:drug effects; D014630:Vagus Nerve / Q000187:drug effects
D011942:Receptors, Adrenergic, alpha; D008750:Methyldopa; D003000:Clonidine; D009638:Norepinephrine
Neue Erkenntnisse über die zentrale Regulation des Blutdruckes. Wirkungsmechanismus von Clonidin und alpha-methyl-DOPA