Abstract
Adrenomedullin (AM) is a multifunctional peptide involved in regulation of cerebral circulation and blood-brain barrier function. Recent studies suggest the protective effects of AM on ischemic brain damage. Effects of AM on cerebral edema, however, have not been investigated. The present study was aimed to investigate the effects of AM and its receptor antagonist, AM22-52, on ischemia-induced cerebral edema in rats using magnetic resonance imaging. Rats were subjected to 1 h of middle cerebral artery occlusion (MCAO) followed by reperfusion. Intravenous injection of AM (1.0 μg/kg), AM22-52 (1.0 μg/kg), or saline was made before MCAO. One day after the surgery, total edema volume, as well as hemispheric swelling, was greatly and significantly reduced by pre-treatment with AM (reduced by 53.2%). The protective effect of AM against edema was more clearly observed in the cerebral cortex (reduced by 62.7%) than the striatum (reduced by 30.7%). Post-treatment with AM had no effects. Pre-treatment with AM22-52 tended to exacerbate the edema. The present study clearly suggests the protective effect of AM against cerebral edema, especially the cortical edema, in rat stroke model. [Jpn J Physiol 54 Suppl:S246 (2004)]
