Proceedings of The Physiological Society
University of Oxford (2011) Proc Physiol Soc 23, PC300
Effects of chelates of gadolinium on intracellular calcium concentrations in isolated rat dorsal root ganglia neurons
H. Kelestimur1, M. Baykara2, M. Ozcan1, M. Sarsilmaz3, B. Yilmaz4, A. Ayar5
1. Firat University, Elazig, Turkey. 2. Education and Research Hospital, Elazig, Turkey. 3. Sifa University, Izmir, Turkey. 4. Yeditepe University, Istanbul, Turkey. 5. Karadeniz Technical University, Trabzon, Turkey.
Chelates of gadolinium are used to provide enhanced contrast between healthy and diseased tissue in nuclear magnetic resonance imaging of different organs. Gadolinium is known to block many types of calcium channels such as stretch-activated and voltage-gated calcium channels. Free gadolinium is highly toxic and can cause a variety of abnormalities. Therefore, it is crucially important that gadolinium should be strongly attached to a ligand to avoid its toxic effects. Nevertheless, some chelates of gadolinium can release gadolinium ion, and they can bring about a wide variety of changes in physiology. In this study, the effects of omniscan and dotarem, which are different types of chelates of gadolinium, on intracellular calcium signalling were investigated in isolated rat sensory neurons (DRG). DRG neurons were loaded with 1 μmol Fura-2 AM, and intracellular calcium responses were assessed by using the fluorescent ratiometry (excitation at 340 and 380 nm, and emission at 510 nm). All data were analyzed by using an unpaired t test, with a 2-tailed P level of <0.05 defining statistical significance. Gadolinium and omniscan caused significant (P<0.001) reductions in KCL-induced increases in intracellular calcium concentration. Intracellular calcium increase evoked by KCL was reduced by 83,4±5,5 % (n=57) and 82,2±5,8 % (n=15) in the presence of omniscan and gadolinium, respectively. Dotarem did not cause any significant change in intracellular calcium concentration, being 98.4±3.2% (n=25). These results indicate that some chelates of gadolinium can inhibit calcium flux in these sensory neurons which might result in side effects in nervous functions.
Where applicable, experiments conform with Society ethical requirements