title: Effects of grape seed proanthocyanidin on 5-hydroxytryptamine(3) receptors in NCB-20 neuroblastoma cells.
abstract: Proanthocyanidin is a phenolic compound present in plants, that has antioxidant, antinociceptive, anti-emetic, and neuroprotective properties. We investigated the actions of proanthocyanidin from grape seeds on 5-hydroxytryptamine (5-HT)(3) receptors in NCB-20 neuroblastoma cells using a whole-cell voltage clamp technique. Co-treatment of proanthocyanidin (0.3-100 µg/ml) and 3 µM 5-HT (near EC(50)) produced a slight inhibition of 5-HT-induced inward peak current (I(5-HT)) in NCB-20 cells, but pretreatment with proanthocyanidin for 30 s before application of 5-HT induced a much larger inhibition of I(5-HT) in an irreversible, concentration- and time-dependent manner (IC(50)=6.5±0.4 µg/ml, Hill coefficient=2.5±0.1). Proanthocyanidin also produced a concentration-dependent inhibition of currents induced by 30 µM 5-HT, near-maximal concentration (IC(50)=22.1±0.4 µg/ml, Hill coefficient=2.4±0.1). High concentrations (≧30 µg/ml) of proanthocyanidin caused a concentration-dependent inhibition of the activation and desensitization of currents induced by 30 µM 5-HT. Further studies showed that pretreatment of 20 µg/ml proanthocyanidin caused not only a rightward shift of the dose-response curve for 5-HT (EC(50) shift from 2.7±0.4 to 6.2±0.5 µM), but also a decreased E(max) (inhibition by 37.5±1.3%). The proanthocyanidin-induced inhibition of 5-HT(3) receptors did not show a significant difference within the testing holding potential ranges (-50-+30 mV). These results suggest that proanthocyanidin inhibits 5-HT(3) receptor function in NCB-20 cells in a noncompetitive mode, and that this inhibitory effect of proanthocyanidin probably contributes to the pharmacological actions of proanthocyanidin.
authors: Department of Pharmacology, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137–701, Korea.
authors: Qing-Zhong
authors: QZ
authors: Li
authors: Hyeong-Seok
authors: HS
authors: Cho
authors: Seung-Hyun
authors: SH
authors: Jeun
authors: Ki Jung
authors: KJ
authors: Kim
authors: Se Joon
authors: SJ
authors: Choi
authors: Ki-Wug
authors: KW
authors: Sung
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D044945:Proanthocyanidins / Q000494:pharmacology*; D044406:Receptors, Serotonin, 5-HT3 / Q000187:drug effects*; D012639:Seeds / Q000737:chemistry*; D012702:Serotonin Antagonists / Q000494:pharmacology; D027843:Vitis / Q000737:chemistry* / Q000196:embryology
chemical_list: D044945:Proanthocyanidins; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists; C013221:proanthocyanidin