Sayers L G, Michelangeli F
School of Biochemistry, University of Birmingham, Edgbaston, U.K.
Biochem Biophys Res Commun. 1993 Dec 30;197(3):1203-8. doi: 10.1006/bbrc.1993.2604.
Inositol 1,4,5-trisphosphate-induced Ca2+ release from rat cerebellar microsomes can be inhibited by polyamines at mM concentrations. Spermine, one of the most abundant naturally occurring polyamines, inhibits InsP3-induced Ca2+ release with an IC50 of 1 mM. However, the antibiotic neomycin proved most efficacious at inhibiting InsP3-induced Ca2+ release (IC50 0.4mM). The order of potency being neomycin > spermine > spermidine > putrescine. Although binding of [3H]InsP3 to cerebellar microsomes is also inhibited by polyamines, this may be due to InsP3 complexing with the polyamines under the binding conditions used. Under Ca2+ release conditions InsP3 binds weakly to spermine and therefore inhibition of InsP3-induced Ca2+ release is consistent with polyamines interacting with the InsP3 receptor.
毫摩尔浓度的多胺可抑制肌醇1,4,5 -三磷酸（InsP3）诱导的大鼠小脑微粒体Ca2+释放。精胺是自然界中含量最丰富的多胺之一，它抑制InsP3诱导的Ca2+释放，半数抑制浓度（IC50）为1毫摩尔。然而，抗生素新霉素在抑制InsP3诱导的Ca2+释放方面最为有效（IC50为0.4毫摩尔）。效力顺序为新霉素>精胺>亚精胺>腐胺。尽管多胺也会抑制[3H]InsP3与小脑微粒体的结合，但这可能是由于在所用的结合条件下InsP3与多胺形成了复合物。在Ca2+释放条件下，InsP3与精胺的结合较弱，因此多胺抑制InsP3诱导的Ca2+释放与多胺与InsP3受体相互作用是一致的。
