Elevation of potassium ion concentration instead of decreasing the chloride content in the extracellular space is sufficient to condition the adult rat brainstem for spreading dep…

Replacing of extracellular chloride ions by an equimolar amount of acetate is appropriate to condition certain brain areas for spreading depression (SD), e.g. the cerebellum (Lauritzen et al., 1988) or the immature brainstem (Richter et al., 2003). This particular procedure, however, failed in the adult rat brainstem. In the present study, we tested whether an elevation of the extracellular potassium concentration ([K+]e) would condition the adult rat brainstem for SD. In sodium thiopentone-anesthetized adult rats (100mg/kg, i.p.) we recorded SD-related DC deflections and changes in [K+]e with ion-selective micr…