Psychophysiological effects of Sideritis herba extracts depend on biologically active ingredients, which might be different for several botanical types of this plant. The present investigation aimed at the characteriz...Psychophysiological effects of Sideritis herba extracts depend on biologically active ingredients, which might be different for several botanical types of this plant. The present investigation aimed at the characterization of extracts from Sideritis scardica and Sideritis euboa in vivo and in vitro. Construction of electropharmacograms on the base of recording of electrical field potentials from four different brain regions was used to compare the possible pharmacological effects to a database of reference drugs with known clinical indications. Whereas Sideritis scardica produced decreases of spectral power in line with stimulatory frequency patterns as observed in the presence of Ginkgo biloba extract, administration of Sideritis euboa produced opposite effects. Electrical stimulation of the Schaffer Collaterals was used to elicit a pyramidal cell response called population spike in vitro. The amplitude of this spike was determined in the presence of single as well as theta burst stimuli. Direct exposure of brain matter to Sideritis scardica extract led to concentration dependent increases of the population spike amplitude under both stimulation patterns in the range from 12.5 to 100 mg/L. On the opposite, extract from Sideritis euboa did not change the electric response up to 50 mg/L. Higher concentrations of this extract attenuated the signal amplitude. A 1:1 blend of both gave intermediate results. The in vitro results are in line with the in vivo EEG recordings, where both extracts induced opposite changes of the electric power with respect to electric frequency patterns. The results from both models suggest a stimulatory and/or memory-enhancing action for the extract from Sideritis scardica but not for Sideritis euboa extract, where a more tranquillizing effect like that observed in the presence of Humulus cone extract may be expected.展开更多
A hydroethanolic extract (20% V/V) from Herba Sideritis scardica has been recognized to positively influence cognition. The present investigation aimed at the question if this extract would be able to modify intra-hip...A hydroethanolic extract (20% V/V) from Herba Sideritis scardica has been recognized to positively influence cognition. The present investigation aimed at the question if this extract would be able to modify intra-hippocampal communication after oral administration of 100 mg/kg daily for one week. The glutamatergic synapse between Schaffer Collaterals and pyramidal cells can be tested by electric stimulation using single pulses or theta burst stimulation. The resulting population spike is modulated by compounds acting at the central nervous system or other preparations directly or as ex vivo approach. In this case the effect of the special extract was tested in vitro the next day after repetitive in vitro administration. Conventional recording technique in the in vitro hippocampus slice revealed an increase of the population spike in the presence of single stimuli and theta burst stimuli resulting in increased long-term potentiation. This effect was tried to modulate by several glutamate receptor antagonists, among them compounds targeting at the ionic NMDA receptor (CGS19755), AMPA receptor (NBQX), Kainate receptor (UBP301) and targeting at three metabotropic glutamate receptors (mGluR I (YM298198), mGluRII ((RS)-APICA)) and mGluRIII (MSOP). Only NBQX was able to prevent the action of the Sideritis scardica extract. Since the AMPA receptor has been related to cognition in several reports in the literature, it is concluded from this result that the positive action of Sideritis scardica extract on brain function involves a modulation of AMPA receptor dependent neurotransmission.展开更多
文摘Psychophysiological effects of Sideritis herba extracts depend on biologically active ingredients, which might be different for several botanical types of this plant. The present investigation aimed at the characterization of extracts from Sideritis scardica and Sideritis euboa in vivo and in vitro. Construction of electropharmacograms on the base of recording of electrical field potentials from four different brain regions was used to compare the possible pharmacological effects to a database of reference drugs with known clinical indications. Whereas Sideritis scardica produced decreases of spectral power in line with stimulatory frequency patterns as observed in the presence of Ginkgo biloba extract, administration of Sideritis euboa produced opposite effects. Electrical stimulation of the Schaffer Collaterals was used to elicit a pyramidal cell response called population spike in vitro. The amplitude of this spike was determined in the presence of single as well as theta burst stimuli. Direct exposure of brain matter to Sideritis scardica extract led to concentration dependent increases of the population spike amplitude under both stimulation patterns in the range from 12.5 to 100 mg/L. On the opposite, extract from Sideritis euboa did not change the electric response up to 50 mg/L. Higher concentrations of this extract attenuated the signal amplitude. A 1:1 blend of both gave intermediate results. The in vitro results are in line with the in vivo EEG recordings, where both extracts induced opposite changes of the electric power with respect to electric frequency patterns. The results from both models suggest a stimulatory and/or memory-enhancing action for the extract from Sideritis scardica but not for Sideritis euboa extract, where a more tranquillizing effect like that observed in the presence of Humulus cone extract may be expected.
文摘A hydroethanolic extract (20% V/V) from Herba Sideritis scardica has been recognized to positively influence cognition. The present investigation aimed at the question if this extract would be able to modify intra-hippocampal communication after oral administration of 100 mg/kg daily for one week. The glutamatergic synapse between Schaffer Collaterals and pyramidal cells can be tested by electric stimulation using single pulses or theta burst stimulation. The resulting population spike is modulated by compounds acting at the central nervous system or other preparations directly or as ex vivo approach. In this case the effect of the special extract was tested in vitro the next day after repetitive in vitro administration. Conventional recording technique in the in vitro hippocampus slice revealed an increase of the population spike in the presence of single stimuli and theta burst stimuli resulting in increased long-term potentiation. This effect was tried to modulate by several glutamate receptor antagonists, among them compounds targeting at the ionic NMDA receptor (CGS19755), AMPA receptor (NBQX), Kainate receptor (UBP301) and targeting at three metabotropic glutamate receptors (mGluR I (YM298198), mGluRII ((RS)-APICA)) and mGluRIII (MSOP). Only NBQX was able to prevent the action of the Sideritis scardica extract. Since the AMPA receptor has been related to cognition in several reports in the literature, it is concluded from this result that the positive action of Sideritis scardica extract on brain function involves a modulation of AMPA receptor dependent neurotransmission.
