Mechanical and metabolic toxicity of 3-(trimethylsilyl)propanesulfonic acid to porcine carotid arteries.

3-(Trimethylsilyl)propanesulfonic acid (TMSPS) is used as a water-soluble NMR frequency marker. It has its major resonance at 0.00 ppm relative to trimethylsilane, and smaller resonances at 0.62, 1.77 and 2.85 ppm. Its toxicity was tested by exposing contracted porcine carotid strips to increasing concentrations of TMSPS. Up to 3 mM, no statistical change in tension was found. Tension decreased 94 +/- 2% (S.E.) after 30 min in 10 mM TMSPS. An intermediate concentration of TMSPS (6 mM) caused a small fall in phosphocreatine in unstimulated perfused porcine carotid arteries (82 +/- 2% S.E.). A larger decrease (59 +/- 6% S.E.) occurred during K+ contractures in the presence of 6 mM TMSPS. From those experiments it appears the TMSPS is non-toxic in concentrations up to 3 mM, but at greater concentrations inhibits both contraction and phosphorus metabolism.