Pharmacological effects of Withania somnifera root extract on GABAA receptor complex.
A methanolic extract of W. somnifera root inhibited the specific binding of [3H]GABA and [35S]TBPS, and enhanced the binding of [3H]flunitrazepam to their putative receptor sites. The extract (5 micrograms) inhibited [3H]GABA binding by 20 +/- 6 per cent whereas a concentration of 1 mg of the extract produced 100 per cent inhibition. The extract (5-100 micrograms) produced 20 +/- 4 to 91 +/- 16 per cent enhancement of [3H]flunitrazepam binding. In functional studies using 36Cl-influx assay in mammalian spinal cord neurons, W. somnifera root extract increased 36Cl-influx in the absence of GABA. This effect on 36Cl-influx was blocked by bicuculline and picrotoxin; and enhanced by diazepam. These results suggest that the W. somnifera extract contains an ingredient which has a GABA-mimetic activity.
Mehta
A K
AK
Department of Pharmacology, University of Texas Health Science Center.
Binkley
P
P
Gandhi
S S
SS
Ticku
M K
MK
D000818:Animals; D002712:Chlorides / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D010936:Plant Extracts / Q000494:pharmacology*; D011247:Pregnancy; D011963:Receptors, GABA-A / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D002712:Chlorides; D010936:Plant Extracts; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid