Nifedipine improves blood flow and oxygen supply, but not steady-state oxygenation of tumours in perfusion pressure-controlled isolated limb perfusion.
Bottom Line: Perfusion was performed by cannulation of the femoral artery and vein in rats bearing DS-sarcoma on the hind foot dorsum.Following equilibration, nifedipine was continuously infused for 30 min (8.3 microg min(-1) kg(-1) BW).Despite the increased oxygen availability (+63%) seen upon application of this calcium channel blocker, nifedipine does not result in a substantial reduction of tumour hypoxia, most probably due to an increase in O(2) uptake with rising O(2) supply to the tumour-bearing hind limb.
Affiliation: Institute of Physiology and Pathophysiology, University of Mainz, Duesbergweg 6, 55099 Mainz, Germany. OLTHEWS@uni-mainz.deShow MeSH
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Mentions: Baseline PP in the isolated-perfused leg before administration of nifedipine or vehicle was 141±8 and 131±7 mmHg, respectively, at comparable baseline perfusate flow rates of 1.09±0.10 ml min−1 in the nifedipine group and of 1.16±0.12 ml min−1 in control animals. Upon nifedipine application, PP initially dropped (with lowest values at t=3 min) to 81% of the baseline value. Thereafter however, the decrease was intentionally compensated by the increased perfusate flow rate resulting in a constant PP of between 130 and 135 mmHg. During nifedipine application, the perfusate flow rate had to be increased by almost 100% in order to maintain a constant PP (Figure 2Figure 2
Affiliation: Institute of Physiology and Pathophysiology, University of Mainz, Duesbergweg 6, 55099 Mainz, Germany. OLTHEWS@uni-mainz.de