Effects of Valeriana officinalis extracts on [3H]flunitrazepam binding, synaptosomal [3H]GABA uptake, and hippocampal [3H]GABA release.
Extracts of Valeriana officinalis have been used in folkloric medicine for its sedative, hypnotic, tranquilizer and anticonvulsant effects, and may interact with gamma-aminobutyric acid (GABA) and/or benzodiazepine sites. At low concentrations, valerian extracts enhance [3H]flunitrazepam binding (EC50 4.13 x 10(-10) mg/ml). However, this increased [3H]flunitrazepam binding is replaced by an inhibition at higher concentrations (IC50 of 4.82 x 10(-1) mg/ml). These results are consistent with the presence of at least two different biological activities interacting with [3H]flunitrazepam binding sites. Valerian extracts also potentiate K+ or veratridine-stimulated release of radioactivity from hippocampal slices preloaded with [3H]GABA. Finally, inhibition of synaptosomal [3H]GABA uptake by valerian extracts also displays a biphasic interaction with guvacine. The results confirm that valerian extracts have effects on GABA(A) receptors, but can also interact at other presynaptic components of GABAergic neurons.
Ortiz
J G
JG
Department of Pharmacology and Toxicology, University of Puerto Rico School of Medicine, San Juan 00936-5067, USA. JG_ORTIZ@YAHOO.COM
Nieves-Natal
J
J
Chavez
P
P
D000818:Animals; D004357:Drug Synergism; D005260:Female; D005445:Flunitrazepam / Q000378:metabolism*; D018757:GABA Modulators / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D008519:Medicine, Traditional; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D014316:Tritium; D014701:Veratridine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D018757:GABA Modulators; D010936:Plant Extracts; D014316:Tritium; D005680:gamma-Aminobutyric Acid; D005445:Flunitrazepam; D014701:Veratridine; D011188:Potassium