The pre-ischaemic neuroprotective effect of a novel polyamine antagonist, N ¹-dansyl-spermine in a permanent focal cerebral ischaemia model in mice

The polyamine sites on the NMDA receptor complex offer a therapeutic target for focal ischaemia, potentially devoid of most side effects associated with NMDA antagonists. In this study, we investigated the effect of a novel polyamine antagonist, N ¹-dansyl-spermine (0.5-10 mg kg ^-1) in a permanent focal cerebral ischaemia model in mice, and compared its effect to that of MK-801 (0.3-3 mg kg ^-1) following administration 30 min prior to ischaemia. A battery of histological and behavioural tests was employed following permanent middle cerebral artery occlusion to assess any neuroprotective effect. Following middle cerebral artery occlusion, N ¹-dansyl-spermine (1-5 mg kg ^-1) and MK-801 (1 or 3 mg kg ^-1) caused a comparable and significant reduction in the percentage hemisphere lesion volume. Similarly, both drugs significantly reduced oedema and neurological deficit score to a similar extent. Locomotor activity in MCAO mice was not significantly improved by MK-801 or N ¹-dansyl-spermine, although N ¹-dansyl-spermine induced a trend towards significant improvement. Significant improvement in rotarod performance was observed at neuroprotective doses with both drugs. Upon comparison of the profile of effects, N ¹-dansyl-spermine at least matched the effectiveness of MK-801 as a neuroprotective agent in this model. In addition, in sham-operated control mice, N ¹-dansyl-spermine was well tolerated, in contrast to the pronounced adverse effects of MK-801 on locomotor activity and rotarod performance. In conclusion, this study has shown that N ¹-dansyl- spermine is as effective a neuroprotective drug as MK-801 in this model. Moreover, in contrast to MK-801, N ¹-dansyl-spermine could be a promising therapeutic candidate for stroke as it is well tolerated at neuroprotective doses in sham-operated animals.