title: The effects of an Echinacea preparation on synaptic transmission and the firing properties of CA1 pyramidal cells in the hippocampus.
abstract: Traditionally, Echinacea preparations are used as antiinflammatory agents and immune-enhancers. In addition to these effects, their anxiolytic potency has been recognized recently in laboratory tests. Our aim in this study was to uncover the potential effects of an Echinacea preparation on neuronal operations in the hippocampus, a brain region that is involved in anxiety and anxiety-related behaviors. Using in vitro electrophysiological techniques, we observed that excitatory synaptic transmission in hippocampal slices was significantly suppressed by an Echinacea extract found to be effective in anxiety tests. In contrast, no change in inhibitory synaptic transmission could be detected upon application of this extract. In addition, our experiments revealed that at low concentration the Echinacea extract reduced the spiking activity of CA1 pyramidal cells, while at high concentration increased it. This latter observation was parallel to the reduction in the magnitude of the h-current-mediated voltage responses in pyramidal cells. At any concentrations, the passive membrane properties of CA1 pyramidal cells were found to be unaltered by the Echinacea extract. In summary, the Echinacea extract can significantly regulate excitatory, but not inhibitory, synaptic transmission in the hippocampus, and this action might be involved in its anxiolytic effects observed in behaviour tests.
authors: Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary. hajos@koki.hu
authors: Norbert
authors: N
authors: Hájos
authors: Noémi
authors: N
authors: Holderith
authors: Beáta
authors: B
authors: Németh
authors: Orsolya I
authors: OI
authors: Papp
authors: Gergely G
authors: GG
authors: Szabó
authors: Rita
authors: R
authors: Zemankovics
authors: Tamás F
authors: TF
authors: Freund
authors: József
authors: J
authors: Haller
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000737:chemistry / Q000494:pharmacology; D020900:Echinacea / Q000737:chemistry*; D055724:Electrophysiological Phenomena; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D008517:Phytotherapy; D028321:Plant Preparations / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D017966:Pyramidal Cells / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects*
chemical_list: D014151:Anti-Anxiety Agents; D028321:Plant Preparations