Synaptosomal GABA release as influenced by valerian root extract--involvement of the GABA carrier.
The effect of an aqueous extract obtained from the roots of Valeriana officinalis was investigated on the uptake and release of GABA in synaptosomes isolated from rat brain cortex. Aqueous extract of valerian inhibited the uptake and stimulated the release of [3H]GABA, either in the absence or in the presence of K+ depolarization. The release was Na(+)-dependent and independent of the presence of Ca2+ in the external medium. It is concluded that valerian extract releases [3H]GABA by reversal of the GABA carrier, which is Na(+)-dependent and Ca(2+)-independent. This increase in [3H]GABA release appears to be independent from Na(+)-K(+)-ATPase activity and the membrane potential.
Santos
M S
MS
Department of Zoology, Faculty of Medicine, University of Coimbra, Portugal.
Ferreira
F
F
Cunha
A P
AP
Carvalho
A P
AP
Ribeiro
C F
CF
Macedo
T
T
D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002794:Choline / Q000494:pharmacology; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D050485:GABA Plasma Membrane Transport Proteins; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D027361:Organic Anion Transporters; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D014632:Valerian; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000596:Amino Acids; D002352:Carrier Proteins; D050485:GABA Plasma Membrane Transport Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D027361:Organic Anion Transporters; D010936:Plant Extracts; D005680:gamma-Aminobutyric Acid; D000254:Sodium-Potassium-Exchanging ATPase; D002794:Choline; D011188:Potassium