Technetium-99m-tetrofosmin, Technetium-99m-MIBI and Thallium-201 uptake in rat myocardial cells

Ali S. Arbab, Kiyoshi Koizumi, Keiji Toyama, Takao Arai, Tsutomu Araki

Research output: Contribution to journalArticle

82 Scopus citations

Abstract

The mechanisms of uptake and intracellular distribution of 99mTc- tetrofosmin, 99mTc-MIBI and 201TI and the behaviors of 99mTc- tetrofosmin and 99mTc-MIBI in relation to Na+ were studied with primary cultures of myocardial cells. Methods: Both the uptake and the washout of the tracers were sequentially measured. The cells were treated with ouabain, bumetanide, tetrodotoxin, dimethyl amiloride (DMA), nigericin and carbonyl cyanide m-chlorophenylhydrazone (CCCP) to observe the effects of the uptake and intracellular distribution of the traders. Cells equilibrated in buffers with or without Na+ were treated with monensin and DMA to evaluate the effect of Na+ on the accumulation of the tracers. Results: Despite the similarities in uptake kinetics, there was a higher level of retention of 99mTc-tetrofosmin inside the cells. Ouabain, bumetanide and tetrodotoxin did not show any inhibitory effect on the uptake of 99mTc-tetrofosmin and 99mTc-MIBI, whereas they produced various degrees of inhibition of 201TI uptake. DMA produced approximately 35% inhibition of 99mTc- tetrofosmin uptake and 50% inhibition of 99mTc-MIBI uptake. Nigericin increased the uptake of 99mTc-MIBI by the cells. The addition of CCCP produced the release of 38% of the accumulated 99mTc-tetrofosmin and 52%- 70% of the accumulated 99mTc-MIBI, indicating that these percentages of accumulation were related to mitochondrial uptake. Neither Na+ -free buffer nor monensin had any significant effect on 99mTc-tetrofosmin accumulation, but they both caused increased accumulation of 99mTc-MIBI. Conclusion: The uptake of both 99mTc-tetrofosmin and 99mTc-MIBI through the cell membrane is partly related to the Na+/H+ antiporter system. Only part of the accumulated 99mTc-tetrofosmin inside the cells enters into mitochondria; most of the accumulated 99mTc-MIBI is related to mitochondrial uptake. This uptake may be related to Na+.

Original languageEnglish (US)
Pages (from-to)266-271
Number of pages6
JournalJournal of Nuclear Medicine
Volume39
Issue number2
StatePublished - Feb 1 1998

Keywords

  • Ion transport inhibitors
  • Myocardial cell
  • Technetium-99m-MIBI
  • Technetium-99m-tetrofosmin
  • Thallium-201

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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