Effects of oral administration of extracts of Hypericum perforatum (St John's wort) on brain serotonin transporter, serotonin uptake and behaviour in mice.
The pharmacological effects of extracts of Hypericum perforatum (St John's wort) were characterized in-vitro and ex-vivo, in relation to its behavioural effects. In in-vitro experiments, St John's wort inhibited brain synaptosomal [(3)H]serotonin uptake in mice with little effect on specific [(3)H]paroxetine binding. For selective serotonin-reuptake inhibitors (SSRIs), the IC50 value for [(3)H]serotonin uptake (molar concentration of unlabelled drug necessary to displace 50% of specific uptake) correlated well with the inhibition constant K(i) value for [(3)H]paroxetine binding in mouse brain. Oral administration of St John's wort (900 mg kg(-1)), paroxetine (1 mg kg(-1)) and sertraline (10 mg kg(-1)) brought about significant increases in the K(m) value for [(3)H]serotonin uptake into brain synaptosomes 4 h later, and only SSRIs suppressed specific [(3)H]paroxetine binding in mouse brain. St John's wort and SSRIs significantly inhibited marble-burying behaviour in mice and the time-course of attenuation of this behaviour by St John's wort was similar to that of [(3)H]serotonin uptake inhibition. In the forced swimming test, St John's wort, but not SSRIs, suppressed the immobility time of mice after oral administration. These results provide the first in-vivo evidence to suggest that the mode of antidepressant action of St John's wort differs from that of SSRIs. Thus, this study may have a significant impact on phytotherapy with St John's wort.
Hirano
Kazufumi
K
Department of Biopharmaceutical Sciences and COE Program in the 21st Century, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
Kato
Yasuhiro
Y
Uchida
Shinya
S
Sugimoto
Yumi
Y
Yamada
Jun
J
Umegaki
Keizo
K
Yamada
Shizuo
S
D000284:Administration, Oral; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020902:Hypericum; D008124:Locomotion / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D012701:Serotonin / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D010936:Plant Extracts; D050486:Serotonin Plasma Membrane Transport Proteins; C493231:Slc6a4 protein, mouse; D012701:Serotonin