Effects of ion channel modulators in the influx and efflux of Tc-99m- MIBI

Ali Syed Arbab, Kiyoshi Koizumi, Keiji Toyama, Takao Arai, Tsutomu Araki

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Possible involvement of cell membrane ion transport systems in the uptake and extrusion of Tc-99m-MIBI was investigated by using various buffers with or without Na+ and Ca++, and ion transport inhibitors in a tumor cell line. The ion transport modulators dimethyl amiloride (DMA), verapamil, flunarizine and monensin were used. The uptake of Tc-99m-MIBI was significantly increased in all buffers containing either Na+ or Ca++ alone or none of them. There was significantly increased uptake of Tc-99m-MIBI especially in buffers without Na+. Verapamil, a L-type Ca++ channel blocker, increased Tc-99m-MIBI uptake in all buffers. Flunarizine, which inhibits Na+/Ca++ channels, caused significantly increased accumulation of Tc-99m-MIBI only in buffer containing both Na+ and Ca++. Monensin, a sodium ionophore, significantly increased uptake of Tc-99m-MIBI. DMA, a potent Na+/H+ antiport inhibitor, significantly inhibited the uptake of Tc- 99m-MIBI in all buffers. In conclusion, Tc-99m-MIBI behaves like Na+ during its uptake and extrusion. Extrusion of Tc-99m-MIBI may involve both verapamil- and flunarizine-sensitive pathways.

Original languageEnglish (US)
Pages (from-to)27-32
Number of pages6
JournalAnnals of Nuclear Medicine
Issue number1
StatePublished - Feb 1999
Externally publishedYes


  • Flunarizine
  • Na/Ca channels
  • Tc-99m-MIBI
  • Tumor cells
  • Verapamil

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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