Effects of erythrocyte lysate of different incubation times on intracellular free calcium in rat basilar artery smooth-muscle cells

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Abstract
Object. The purpose of this study was to characterize substance(s) in the erythrocytes that increase intracellular free Ca++ concentration ([Ca++]i) in smooth-muscle cells and that therefore may be involved in the pathogenesis of vasospasm. Methods. Because vasospasm occurs days after subarachnoid hemorrhage (SAH), the authors studied the effects of aged human erythrocyte hemolysate and its low-molecular-weight (LMW) and high-molecular-weight (HMW) fractions on [Ca++]i in freshly isolated rat basilar artery smooth-muscle cells. Fresh hemolysate (Day 0) produced a biphasic response consisting of a transient peak and a sustained plateau increase in [Ca++]i, whereas hemolysate prepared from cells incubated for 3, 7, or 14 days induced only a transient response without a sustained phase. The effect of hemolysate declined with increasing incubation time. The HMW fraction and purified human oxyhemoglobin (OxyHb) did not evoke a response. The LMW fraction from Days 3, 7, or 14 produced no response at low concent...