Possible Interaction: Norepinephrine and St John's Wort

“ St. John's wort extract has a clear inhibitory effect on the neuronal uptake not only of serotonin, noradrenaline , and dopamine but also of gamma-aminobutyric acid (GABA) and L-glutamate.”

“Like other working parties, we were only able to identify a weak inhibitory effect of the extract and the pure substance hypericin on the monoamine oxidases A and B. Similarly to synthetic antidepressants, St-John's wort exerts marked inhibitory effects on synaptosomal uptake of serotonin and noradrenaline.”

“In addition, St. John's wort is a potent uptake inhibitor of the neurotransmitters serotonin, norepinephrine and dopamine all of which have a role in mood control.”

“Classic synthetic antidepressant drugs, as well as St John's wort extract (SJW), directly inhibit the re‐uptake of norepinephrine (NE) and/or serotonin (5‐HT) into pre‐synaptic axons.”

“Both 5-HT and NA might concomitantly contribute to the effects of different antidepressants in the "low-dose scopolamine" model; (3) hypericum might enhance both 5-HT and NA transmission in forebrain limbic brain circuits important for mood control, which could underly its antidepressant effects.”

“In our previous investigations, we could demonstrate that extract preparations of Hypericum perforatum (St. John's wort, SJW) inhibit the uptake of several neurotransmitters (serotonin, norepinephrine , dopamine, GABA, L-glutamate) in synaptosomal preparations of rodent brain.”

“ Hyperforin-free Hypericum extract also elevates the extracellular concentrations of dopamine and norepinephrine in the locus coeruleus, but, in contrast to hyperforin, the extracellular concentration of serotonin is diminished.”

“On the other hand, IHp treatment significantly augmented the levels of norepinephrine (NE) and its metabolite methylhydroxy phenyl glycol (MHPG) and NE turnover in all the brain regions studied.”

“ Hypericum extract (Ph-50; 250-500 mg/kg) with acute oral administration enhanced serotonin, norepinephrine and dopamine content in the brain and reduced the immobility time of rats in the forced-swimming test.”