Effect of SJAMP on human platelet cytoplasmic Ca²⁺

Abstract

Using the method of dual-wavelength measurement of platelet [Ca²⁺]_i and Fura-2 as the Ca²⁺ fluorophore probe, we measured the effect of acidic Mucopolysaccharide fromSticopus Japonicus Selenka (SJAMP) on platelet [Ca²⁺]_i. The results showed that the most significant increase in platelets [Ca²⁺]_i was seen when the concentration of SJAMP was 100μg/ml and the elevation of normal platelet [Ca²⁺]_i was 93.96 ± 10.24 nmol/L (n=10). In the presence of extracellular Ca²⁺ (1 mmol/L), the magnitude of platelet [Ca²⁺]_i response to SJAMP was increased and the [Ca²⁺]_i could reach 116.72±10. 66 nmol/L (n = 10). On the other hand, the magnitude of increased platelet [Ca²⁺]_i induced by SJAMP was smaller and the duration of [Ca²⁺]_i reaching the highest level was longer when compared with other platelet aggregation agents. In the mean time, if platelets were first incubated with cyclooxygenase inhibitor, the rise of [Ca²⁺]_i evoked by SJAMP was inhibited. The results indicated that the mechanism of the rise of [Ca²⁺]_i induced by SJAMP might be dependent upon the generation of prostaglandin endoperoxides and(or) TXA₂.

Keywords

SJAMP / platelet cytoplasmic Ca²⁺

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