The effects of (-)clausenamide on functional recovery in transient focal cerebral ischemia

The effects of (-)clausenamide (clau) on spatial cognitive functions and hippocampal long-term potentiation (LTP) after transient focal cerebral ischemia in rats were investigated. Four weeks after middle cerebral artery occlusion, Morris water maze tasks demonstrated that 2 h of transient forebrain ischemia resulted in a significant decrease in spatial discrimination performance. The escape latency at 4 and 5 days of acquisition trial was lower in the ischemic rats than in sham-operated rats (33.8 +/- 6.7sec and 26.8 +/- 5 sec versus 12.2 +/- 4.Osec and 10.4 +/- 3.6sec), chronic treatment with clau (10 mg kg(-1) p.o. once daily) significantly improved the impairment (12.4 +/- 4.1 sec and 15.2 +/- 3.1 sec). After Morris water maze, the changes in population spike (PS) amplitude were recorded as an index of LTP in the perforant path-dentate gyrus synapses. There was no difference in PS amplitude between the sham-operated and vehicle-treated animals, whereas the fractional increase of PS 20-50 min after tetanus was significantly larger in clau-treated group. Histopathological analysis revealed that clau could protect against neuron loss in the regions of cortex and striatum. In conclusion, these data indicate a beneficial effect of clau for synaptic plasticity and cognitive function impaired by transient focal cerebral ischemia.