title: The methanolic extract of Withania somnifera ACTS on GABAA receptors in gonadotropin releasing hormone (GnRH) neurons in mice.
abstract: The effect of the methanol extract of Withania somnifera (mWS) on the gonadotropin releasing hormone (GnRH) neuron was examined in juvenile mice using the whole cell patch clamp technique. GnRH neurons are the fundamental regulators of the pulsatile release of GnRH needed for puberty and fertility. GnRH neurons were depolarized by bath application of the mWS (400 ng/microl) under the condition of a high Cl(-) pipette solution in current clamp mode. In voltage clamp mode, mWS induced reproducible inward currents (31.7 +/- 5.51 pA, n = 14). The mWS-induced inward currents persisted in the presence of tetrodotoxin (TTX, 0.5 microM), but were suppressed by bicuculline methiodide (BMI, 20 microM), a GABA(A) receptor antagonist. These results show that mWS affects the neuronal activities by mediating the GABA(A) receptor, which suggests that WS contains an ingredient with possible GABAmimetic activity.
authors.affiliation: Department of Oral Physiology and BK21 program, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, 561-756, Republic of Korea.
authors.forename: Janardhan P
authors.initials: JP
authors.lastname: Bhattarai
authors.forename: Seon
authors.initials: S
authors.lastname: Ah Park
authors.forename: Seong Kyu
authors.initials: SK
authors.lastname: Han
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D058787:GABA-A Receptor Antagonists; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D010936:Plant Extracts / Q000494:pharmacology*; D011963:Receptors, GABA-A / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology; D032341:Withania / Q000737:chemistry*
chemical_list: D058787:GABA-A Receptor Antagonists; D010936:Plant Extracts; D011963:Receptors, GABA-A; D007987:Gonadotropin-Releasing Hormone; C017069:bicuculline methiodide; D013779:Tetrodotoxin; D001640:Bicuculline