title: Effects of ginsenosides on carbachol-stimulated formation of inositol phosphates in rat cortical cell cultures.
abstract: We examined the effect of ginseng total saponins (GTS) on phosphoinositide metabolism stimulated by activation of muscarinic receptor using rat cortical cultures. Carbachol stimulated formation of [3H]inositol phosphates ([3H]InsPs) by 3.3-fold over basal level in [3H]inositol-prelabeled cells. Pretreatment of GTS inhibited formation of [3H]InsPs evoked by carbachol by 70%-90%. Addition of GTS alone had no effect on the basal formation of [3H]InsPs. The inhibitory effect of the GTS on carbachol-stimulated formation of [3H]InsPs was dose- and time-dependent. IC50 was 6.0 +/- 2.8 microg/ml. We also examined the effect of GTS on [3H]InsP1, [3H]InsP2, or [3H]InsP3 formation evoked by carbachol. Although GTS had no effect on the basal [3H]InsP1, [3H]InsP2, or [3H]InsP3 formation, pretreatment of GTS inhibited [3H]InsP1, [3H]InsP2, or [3H]InsP3 formation evoked by carbachol, respectively. Addition of individual ginsenosides such as ginsenoside Rb1, Rc, Rd, Re, or Rg2 had no effect on the basal formation of [3H]InsPs, whereas pretreatment of ginsenoside Rb2, Rc, Rd, Re, Rf, Rg1 or Rg2 inhibited formation of [3H]InsPs evoked by carbachol by 79%-89%. The results suggest that the inhibitory effect of GTS and its individual ginsenosides on carbachol-stimulated formation of [3H]InsPs in cortical neurons could be one pharmacological action of Panax ginseng.
authors.affiliation: Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Seok
authors.initials: S
authors.lastname: Choi
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Kim
authors.forename: Jae-il
authors.initials: JI
authors.lastname: Kim
authors.forename: Seung-Yeol
authors.initials: SY
authors.lastname: Nah
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D036145:Ginsenosides / Q000494:pharmacology*; D007295:Inositol Phosphates / Q000096:biosynthesis*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats
chemical_list: D036145:Ginsenosides; D007295:Inositol Phosphates; D002217:Carbachol