Effects of S-adenosyl-methionine on plasma norepinephrine, blood pressure, and heart rate in healthy volunteers.
S-adenosyl-methionine (SAMe) is currently undergoing trials as a possible antidepressant. Because SAMe's mechanism of action is obscure and norepinephrine (NE) is often implicated in affective disorders, we studied the effects of SAMe on this neurotransmitter in volunteers. Plasma NE and 3-methoxy-4-hydroxyphenylglycol (MHPG) in the supine and standing position were studied before and after acute placebo or a single 400 mg dose of SAMe and following seven daily administrations; concomitant measures were heart rate (HR) and blood pressure. Subjects were unable to distinguish acute drug from placebo, and although chronic SAMe administration was open, they reported no behavioral effects. Standing HR and plasma NE were reduced following chronic SAMe. Qualitatively similar changes are obtained following chronic treatment with monoamine oxidase inhibitors (MAOIs). However, unlike MAOIs, chronic SAMe treatment was not associated with changes in plasma MHPG. Exaggerated standing NE is found in depressed patients; SAMe may reduce this abnormal response, providing a clue for its mechanism of action in depression.
D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000097:blood; D009638:Norepinephrine / Q000097:blood*; D012436:S-Adenosylmethionine / Q000494:pharmacology*
D008734:Methoxyhydroxyphenylglycol; D012436:S-Adenosylmethionine; D009638:Norepinephrine