5-(N-ETHYL-N-ISOPROPYL)-AMILORIDE INHIBITS AMINO-ACID RELEASE FROM THE ISCHEMIC RAT CEREBRAL-CORTEX - ROLE OF NA-H+ EXCHANGE()

The effect of the selective Na+/H+ antiporter inhibitor 5-(N-ethyl-N-i sopropyl)-amiloride (EIPA) on amino acid release from the ischemic/rep erfused rat cerebral cortex was investigated using a cortical cup tech nique. EIPA (25 mu M in artificial cerebrospinal fluid), applied topic ally, inhibited the ischemia-reperfusion evoked efflux of aspartate, g lutamate, gamma-aminobutyric acid, taurine and phospho ethanolamine. R eductions in the ischemia-evoked releases of these amino acids suggest that ischemia precipitates acidosis, Na+/H+ exchange and cell swellin g with amino acid release as the cells mount a regulatory volume decre ase response. EIPA, by blocking Na+/H+ exchange, would reduce cell swe lling and the resulting amino acid release. (C) 1998 Elsevier Science B.V. All rights reserved.