Spermidine/spermine N-1-acetyl transferase activity in rat brain followingtransient focal cerebral ischemia and reperfusion

The polyamine system is very sensitive to different pathological states of brain and is perturbed after central nervous system (CNS) injury. Spermidin e/Spermine N-1-acetyl transferase (SSAT) is the key enzyme responsible for interconversion of spermine and spermidine to spermidine and putrescine res pectively. In the present study, SSAT activity was evaluated in the rat CNS , following transient focal cerebral ischemia and reperfusion. The middle c erebral artery (MCA) was occluded for 2 h in male spontaneously hypertensiv e rats by an intraluminal suture technique. Animals were sacrificed at 3-24 h reperfusion following the MCA occlusion and SSAT activity was assayed in cortex and striatum. Results showed that SSAT activity was significantly i ncreased at 12 h reperfusion in cortex and at 9, 12 and 18 h reperfusion in striatum following ischemia compared to sham or contralateral controls. Th ese results demonstrate that polyamine catabolism in the rat CNS is altered following MCA occlusion. In the in vitro ischemia study, SSAT activity was evaluated in primary cortical neuronal cultures at 6-24 h re-oxygenation i ntervals following oxygen-glucose deprivation for 1 h, and the results from this group show that the enzyme activity increased by about 62% (P < 0.05) at 24 h re-oxygenation. This study suggests that the increased SSAT activi ty may contribute to the increase in putrescine during the post-ischemic pe riod. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.