title: Isoliquiritigenin suppresses cocaine-induced extracellular dopamine release in rat brain through GABA(B) receptor.
abstract: Glycyrrhizae radix (licorice) comprises a variety of flavonoids as major constituents including isoliquiritigenin, liquiritin, liquiritigenin, and glycyrrihizin. It has shown various biological activities such as anti-inflammatory, anti-carcinogenic and antihistamic. As very little is known in regard to drug addiction, we carried out a study on the effect of G. radix and its active component, isoliquiritigenin, on acute cocaine-induced extracellular dopamine release in moving rats. Male Sprague-Dawley rats were orally administered with methanolic extracts of G. radix or isoliquiritigenin 1 h prior to an injection of cocaine (20 mg/kg, intraperitoneal (i.p.)). Extracellular dopamine was measured by in vivo microdialysis. Extract of G. radix and isoliquiritigenin inhibited cocaine-induced extracellular dopamine level in the nucleus accumbens by dose-dependent manner. Inhibition of dopamine release by isoliquiritigenin resulted in attenuation of the expression of c-Fos, an immediately early gene induced by cocaine. Effect of isoliquiritigenin was completely prevented by a GABA(B) receptor antagonist. Thus, these results showed that G. radix and isoliquiritigenin inhibit cocaine-induced dopamine release by modulating GABA(B) receptor, suggesting that isoliquiritigenin might be effective in blocking the reinforcing effects of cocaine.
authors.affiliation: Department of Physiology, College of Oriental Medicine, Daegu Haany University, Daegu 706-828, South Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Jang
authors.forename: Eun Sang
authors.initials: ES
authors.lastname: Choe
authors.forename: Meeyul
authors.initials: M
authors.lastname: Hwang
authors.forename: Sang Chan
authors.initials: SC
authors.lastname: Kim
authors.forename: Jong Rok
authors.initials: JR
authors.lastname: Lee
authors.forename: Sang Geon
authors.initials: SG
authors.lastname: Kim
authors.forename: Jae-Pil
authors.initials: JP
authors.lastname: Jeon
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Buono
authors.forename: Chae Ha
authors.initials: CH
authors.lastname: Yang
mesh_terms: D000818:Animals; D047188:Chalcones / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003042:Cocaine / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D018765:Dopamine Uptake Inhibitors / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D006035:Glycyrrhiza / Q000737:chemistry; D008297:Male; D017551:Microdialysis; D009025:Morpholines / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018080:Receptors, GABA-B / Q000187:drug effects / Q000378:metabolism*
chemical_list: C095804:(+)-(S)-5,5-dimethylmorpholinyl-2-acetic acid; D047188:Chalcones; D018765:Dopamine Uptake Inhibitors; D004791:Enzyme Inhibitors; D009025:Morpholines; D010936:Plant Extracts; D016760:Proto-Oncogene Proteins c-fos; D018080:Receptors, GABA-B; C040920:isoliquiritigenin; D003042:Cocaine; D004298:Dopamine