5s 9 u03b1s 2s 5r and 1 u03b1s 2r 5s are also particularly preferred compounds the neuroprotective effect of the snc80 against glutamate toxicity in neuronal cell cultures was determined using a standard method of quantifying neuronal damage by measuring ldh release since ldh is a lysosomal enzyme released from damaged neurons into the culture media when neuronal cells are injured one way in which neuronal cells may be damaged is by exposure to glutamate a common agent used to induce neuronal damage in the instant case the damaging effect of gluamate on these cultures as shown to be overcome by exposure to an active agent of the invention table i______________________________________treatment ldh release neuroprotection______________________________________basal no treatment 74 0 u00b1 3 3 glutamate 80 u03bcm 103 9 u00b1 7 8 glutamate snc80 5 u03bcm 98 6 u00b1 4 5 17 glutamate snc80 20 u03bcm 91 0 u00b1 2 0 43 glutamate snc80 40 u03bcm 84 7 u00b1 3 4 63 ______________________________________ units ml u00b1 s e the induced antagonism of glutamate neurotoxic calcium flux was studied with the results shown in table 2 table 2______________________________________ response type sus treatment neurons transient biphasic tained ______________________________________80 u03bcm glutamate 18 4 0 14glutamate 10 3 6 150 u03bcm smc80glutamate 21 3 17 1100 u03bcm.