ISSN:
1432-1912
Schlagwort(e):
Entorhinal cortex
;
Isomers
;
Low magnesium epilepsy
;
Losigamone
;
Maximal electroshock test
;
Mice
;
Rat
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Summary Losigamone (AO-33) is a recemate of a tetronic acid derivative. The effects of losigamone and its three isomers (AO-242, AO-294 and AO-23) were compared on maximal electroshock (MES) induced convulsions in mice and on different patterns of extracellularly recorded, low Mg 2+ induced epileptiform activity in slices of the rat temporal cortex. Lowering Mg 2+ induced recurrent short discharges in areas CA3 and CA1 while ictaform events that lasted for many seconds were induced in the entorhinal cortex. In the hippocampus the activity stayed stable over a number of hours. In contrast, the ictaform events in the entorhinal cortex changed their characteristics after one to two hours to recurrent discharges of 0.8 to 10 s. Afterdischarges and interictal events were absent. 50 μM AO-242 showed a similar efficacy to 50 μM AO-33 in reducing and blocking epileptiform discharges in areas CA1 and CA3 while 50 μM AO-294 and 50 μM AO-23 had weaker effects than 50 μM AO-33. Concentrations of 50 μM and 100 μM AO-242 showed a similar efficacy to AO-33 on ictaform events in the entorhinal cortex. Late recurrent discharges were also blocked by AO-33 and AO-242 although at higher concentrations (300 μM). The in vitro observations are with respect to order of efficacy in accordance with the in vivo data obtained in the maximal electroshock test in mice. The order of potency in the MES test was AO-242〉AO-33≫AO-294≫ AO-23. The results show that the erythro-isomer AO-23, although active, is much less potent than AO-33. Of the two optical isomers of losigamone the (+) isomer AO-242 is more active than the (−) form AO-294.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00175474
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